Abstract

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
Volume10
Issue number1
DOIs
Publication statusPublished - 2003

Keywords

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

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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