Toll-like receptor 4-dependent activation of myeloid dendritic cells by leukocidin of Staphylococcus aureus

Ken Inden, Jun Kaneko, Akiko Miyazato, Natsuo Yamamoto, Shota Mouri, Yoshiyuki Shibuya, Kiwamu Nakamura, Tetsuji Aoyagi, Masumitsu Hatta, Hiroyuki Kunishima, Yoichi Hirakata, Yoshifumi Itoh, Mitsuo Kaku, Kazuyoshi Kawakami

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

Leukocidin (Luk), an exotoxin of Staphylococcus aureus consisting of LukF and LukS, is a hetero-oligomeric pore-forming cytolytic toxin toward human and rabbit polymorphonuclear leukocytes. However, it is uncertain how Luk affects the host immune response. In the present study, we investigated whether Luk has the ability to stimulate mouse bone marrow-derived myeloid dendritic cells (BM-DCs). LukF activated BM-DCs to generate IL-12p40 mRNA, induce intracellular expression and extracellular secretion of this cytokine and express CD40 on their surface, whereas LukS showed a much lower or marginal ability in the activation of BM-DCs than its counterpart component. Similarly, TNF-α was secreted by BM-DCs upon stimulation with these components. Combined addition of these components did not lead to a further increase in IL-12p40 secretion. IL-12p40 production caused by LukF was completely abrogated in BM-DCs from TLR4-deficient mice similarly to the response to lipopolysaccharide (LPS). Polymixin B did not affect the LukF-induced IL-12p40 production, although the same treatment completely inhibited the LPS-induced response. Boiling significantly inhibited the response caused by LukF, but not by LPS. Finally, in a luciferase reporter assay, LukF induced the activation of NF-κB in HEK293T cells transfected with TLR4, MD2 and CD14, whereas LukS did not show such activity. These results demonstrate that LukF caused the activation of BM-DCs by triggering a TLR4-dependent signaling pathway and suggests that Luk may affect the host inflammatory response as well as show a cytolytic effect on leukocytes.

Original languageEnglish
Pages (from-to)245-253
Number of pages9
JournalMicrobes and Infection
Volume11
Issue number2
DOIs
Publication statusPublished - 2009 Feb

Keywords

  • CD40
  • Dendritic cells
  • IL-12
  • Leukocidin
  • Staphylococcus aureus
  • TLR4

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Infectious Diseases

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