Reduction of IL-10 and nitric oxide synthesis by SR31747A (sigma ligand) in RAW murine macrophages.
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.
Gannon
C J
CJ
Department of Surgery, University of Maryland School of Medicine, 10 North Greene Street, Baltimore, MD 21201, USA.
Malone
D L
DL
Napolitano
L M
LM
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
D003510:Cyclohexanes; D008024:Ligands; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D017480:Receptors, sigma; D016753:Interleukin-10; C088447:SR 31747; D019001:Nitric Oxide Synthase