title: Arginase activity in a murine macrophage cell line (RAW264.7) stimulated with lipopolysaccharide from Actinobacillus actinomycetemcomitans.
abstract: OBJECTIVE
  The aim of the present study was to determine whether or not lipopolysaccharide from Actinobacillus actinomycetemcomitans could stimulate arginase activity in a murine macrophage cell line (RAW264.7 cells).
  
  
  METHODS
  RAW264.7 cells were treated with A. actinomycetemcomitans-lipopolysaccharide or lipopolysaccharide from Escherichia coli for 24 h. The effect of polymyxin B, l-norvaline, dl-norvaline, dexamethasone and cytokines (interferon-gamma and interleukin-4) on arginase activity in A. actinomycetemcomitans-lipopolysaccharide-stimulated cells was also determined. The cells were pretreated with anti-CD14, anti -toll-like receptor 2, or anti-toll-like receptor 4 antibody prior to stimulation with A. actinomycetemcomitans-lipopolysaccharide. Arginase activity was determined by a colorimetric assay.
  
  
  RESULTS
  A. actinomycetemcomitans-lipopolysaccharide stimulated arginase activity in RAW264.7 cells in a dose-dependent manner, but was less potent than E. coli-lipopolysaccharide. Polymyxin B and l-norvaline, but not dl-norvaline, blocked the arginase activity in A. actinomycetemcomitans-lipopolysaccharide-stimulated cells. Dexamethasone and interleukin-4 but not interferon-gamma augmented arginase activity in A. actinomycetemcomitans-lipopolysaccharide-stimulated cells. Treatment of the cells with anti-CD14 and anti-toll-like receptor 4 but not anti-toll-like receptor 2 antibody decreased arginase activity in A. actinomycetemcomitans-lipopolysaccharide-stimulated cells.
  
  
  CONCLUSIONS
  The results of the present study suggest that lipopolysaccharide from A. actinomycetemcomitans via CD14/toll-like receptor 4 complex molecules and the regulatory control of glucocorticoid and cytokines may stimulate arginase activity in RAW264.7 cells.
authors.affiliation: Department of Oral Biology, School of Dental Sciences, University Sains Malaysia, Kota Bharu, Malaysia. wihaskoro@kb.usm.my
authors.forename: W
authors.initials: W
authors.lastname: Sosroseno
authors.forename: M
authors.initials: M
authors.lastname: Musa
authors.forename: M
authors.initials: M
authors.lastname: Ravichandran
authors.forename: M
authors.initials: M
authors.lastname: Fikri Ibrahim
authors.forename: P S
authors.initials: PS
authors.lastname: Bird
authors.forename: G J
authors.initials: GJ
authors.lastname: Seymour
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000502:physiology*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001119:Arginase / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D002460:Cell Line; D016207:Cytokines / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D018950:Lipopolysaccharide Receptors / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000276:immunology; D008264:Macrophages / Q000201:enzymology*; D051379:Mice; D011112:Polymyxin B / Q000494:pharmacology; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D016207:Cytokines; D005938:Glucocorticoids; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D003907:Dexamethasone; C005313:norvaline; D001119:Arginase; D014633:Valine; D011112:Polymyxin B