title: Nitric oxide production by a murine macrophage cell line (RAW264.7 cells) stimulated with Aggregatibacter actinomycetemcomitans surface-associated material.
abstract: Nitric oxide (NO) may play a crucial role in the pathogenesis of periodontal disease and, hence, the aim of the present study was to test the hypothesis that Aggregatibacter actinomycetemcomitans surface-associated material (SAM) stimulates inducible nitric oxide synthase (iNOS) activity and NO production by the murine macrophage cell line RAW264.7. Cells were stimulated with untreated or heat-treated A. actinomycetemcomitans SAM and with or without pre-treatment with L-N(6)-(1-Iminoethyl)-lysine (L-NIL) (an iNOS inhibitor), polymyxin B, interferon-gamma (IFN-γ) and Interleukin-4 (IL-4), IL-10, genistein [a protein tyrosine kinase (PTK) inhibitor], bisindolylmaleimide [a protein kinase C (PKC) inhibitor], bromophenacyl bromide (BPB) [a phospholipase A(2) (PLA2) inhibitor] or wortmannin [phosphatidylinositol 3-kinase (PI-3K) inhibitor]. The iNOS activity and nitrite production in the cell cultures were determined. Untreated but not heat-treated A. actinomycetemcomitans SAM-stimulated both iNOS activity and nitrite production in RAW264.7 cells. L-NIL, IL-4, IL-10, genistein, bisindolylmaleimide, or BPB, suppressed but IFN-γ enhanced both iNOS activity and nitrite production by A. actinomycetemcomitans SAM-stimulated cells. Wortmannin and polymyxin B failed to alter both iNOS activity or nitrite production by A. actinomycetemcomitans SAM treated cells. Therefore, the present study suggests that a heat-sensitive protein constituent(s) of A. actinomycetemcomitans SAM stimulates both iNOS activity and nitrite production by RAW264.7 cells in a cytokine, PTK, PKC, and PLA(2) but not PI-3K-dependent fashion.
authors: Faculty of Dentistry, AIMST University, Semeling, Bedong, Kedah Darul Aman, Malaysia. wsosroseno@yahoo.com
authors: W
authors: W
authors: Sosroseno
authors: P S
authors: PS
authors: Bird
authors: G J
authors: GJ
authors: Seymour
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000276:immunology* / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000276:immunology*; D002460:Cell Line; D016207:Cytokines / Q000378:metabolism / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000276:immunology; D006801:Humans; D008070:Lipopolysaccharides / Q000276:immunology*; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D054467:Phospholipases A2 / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D009573:Nitrites; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D054467:Phospholipases A2