This study investigates the signaling pathway involved in inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) release caused by Staphylococcus aureus lipoteichoic acid (LTA) in RAW 264.7 macrophages. A phosphatidylcholine-phospholipase C (PC-PLC) inhibitor (D-609) and a phosphatidylinositol-phospholipase C (PI-PLC) inhibitor (U-73122) attenuated LTA-induced iNOS expression and NO release. Two PKC inhibitors (Go 6976 and Ro 31-8220), an NF-κB inhibitor (pyrrolidine dithiocarbamate; PDTC), and long-term (24 h) 12-phorbol-13-myristate acetate (PMA) treatment each also inhibited LTA-induced iNOS expression and NO release. Treatment of cells with LTA caused an increase in PKC activity; this stimulatory effect was inhibited by D-609, U-73122, or Ro 31-8220. Stimulation of cells with LTA caused IκB-α phosphorylation and IκB-α degradation in the cytosol, and translocation of p65 and p50 NF-κB from the cytosol to the nucleus. Treatment of cells with LTA caused NF-κB activation by detecting the formation of NF-κB-specific DNA-protein complexes in the nucleus; this effect was inhibited by Go 6976, Ro 31-8220, long-term PMA treatment, PDTC, L-1-tosylamido-2-phenylethyl chloromethyl ketone (TPCK), and calpain inhibitor I. These results suggest that LTA might activate PC-PLC and PI-PLC to induce PKC activation, which in turn initiates NF-κB activation, and finally induces iNOS expression and NO release in RAW 264.7 macrophages.

Original languageEnglish
Pages (from-to)136-145
Number of pages10
JournalJournal of Biomedical Science
Issue number1
Publication statusPublished - 2003


  • Inducible nitric oxide synthase
  • Lipoteichoic acid
  • NF-κB
  • Nitric oxide
  • Protein kinase C
  • RAW 264.7 macrophages

ASJC Scopus subject areas

  • Biochemistry, medical
  • Pharmacology (medical)
  • Molecular Biology
  • Clinical Biochemistry
  • Endocrinology, Diabetes and Metabolism
  • Cell Biology


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