title: Reduction of IL-10 and nitric oxide synthesis by SR31747A (sigma ligand) in RAW murine macrophages.
abstract: BACKGROUND
  There are several subtypes of sigma receptor, one of which is found throughout the immune system. SR31747A is a unique sigma ligand that possesses potent immune modulatory properties. Previous in vivo studies have documented that administration of SR31747A in murine models of sepsis resulted in decreased proinflammatory (IL-1, IL-6, TNF-alpha) and increased anti-inflammatory (IL-10) response (serum, splenocyte). Studies regarding the effect of this sigma ligand on purified macrophages are lacking. We therefore sought to investigate the effect of SR31747A in LPS-stimulated murine macrophages (RAW 264.7).
  
  
  METHODS
  RAW cells were incubated at 2.5 x 10(5) cells/well; controls were incubated with media alone, experimental groups contained LPS (0.01 microg) and SR31747A (1 nM, 10 nM, 100 nM, 1 microM, 10 microM). Supernatant and cells were harvested at 24 and 48 h. Concentrations of nitric oxide (Greiss reaction) and IL-10 were determined in the supernatant; cellular IL-10 mRNA was assessed.
  
  
  RESULTS
  SR31747A induced a dose-dependent reduction in NO and IL-10 protein release in LPS-stimulated murine macrophages. The decrease in IL-10 protein synthesis was paralleled by a significant dose-dependent reduction in IL-10 mRNA.
  
  
  CONCLUSIONS
  SR31747A is a novel immunomodulator that down regulates nitric oxide and IL-10 protein and mRNA expression. This in vitro reduction of IL-10 protein and mRNA expression is in contrast to previous in vivo murine studies. These data suggest that peripheral macrophages are not the source of the increased anti-inflammatory (IL-10) response induced by SR31747A.
authors.affiliation: Department of Surgery, University of Maryland School of Medicine, 10 North Greene Street, Baltimore, MD 21201, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Gannon
authors.forename: D L
authors.initials: DL
authors.lastname: Malone
authors.forename: L M
authors.initials: LM
authors.lastname: Napolitano
mesh_terms: D000818:Animals; D003510:Cyclohexanes / Q000494:pharmacology*; D004195:Disease Models, Animal; D066298:In Vitro Techniques; D016753:Interleukin-10 / Q000032:analysis* / Q000235:genetics; D008024:Ligands; D008070:Lipopolysaccharides / Q000009:adverse effects; D008264:Macrophages / Q000187:drug effects* / Q000502:physiology*; D051379:Mice; D019001:Nitric Oxide Synthase / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D017480:Receptors, sigma / Q000187:drug effects / Q000502:physiology; D018805:Sepsis / Q000139:chemically induced / Q000503:physiopathology*; D013997:Time Factors
chemical_list: D003510:Cyclohexanes; D008024:Ligands; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D017480:Receptors, sigma; D016753:Interleukin-10; C088447:SR 31747; D019001:Nitric Oxide Synthase