Receptor-mediated activation of murine peritoneal macrophages by antithrombin III acts as a costimulatory signal for nitric oxide synthesis.
We evaluated the effect of antithrombin III (ATIII), a serine protease inhibitor (SERPIN), on induction of nitric oxide (NO) synthesis in murine peritoneal macrophages. Incubation of macrophages with ATIII plus interferon-gamma (IFN-gamma) but not ATIII alone induced nitrite accumulation (a metabolite of NO) in a dose-dependent manner. Expression of the inducible nitric oxide synthase isoform was confirmed by Western blot. NO synthesis was inhibited by NG-monomethyl-l-arginine, by complexing ATIII with thrombin or by rabbit anti-human ATIII antiserum. Addition of polymyxin B to macrophage cultures failed to inhibit ATIII/IFN-gamma-induced NO synthesis, excluding lipopolysaccharide contamination. 125I-ATIII bound to macrophages in a dose-dependent, specific, and saturable manner, with a Km of approximately 7.1 nM. Our results demonstrate that ATIII, but not ATIII/thrombin complex, acts to costimulate macrophage activation and NO synthesis via a novel receptor mediated mechanism, which may indicate a role for SERPINs in macrophage activation.
Kwak
J Y
JY
Department of Internal Medicine, Chonbuk National University Medical School, Chonju, Chonbuk, 560-182, Korea.
Park
S Y
SY
Han
M K
MK
Lee
H S
HS
Sohn
M H
MH
Kim
U H
UH
McGregor
J R
JR
Samlowski
W E
WE
Yim
C Y
CY
D000818:Animals; D000990:Antithrombin III / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D007371:Interferon-gamma / Q000494:pharmacology; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008262:Macrophage Activation / Q000187:drug effects; D017737:Macrophages, Peritoneal / Q000276:immunology* / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000096:biosynthesis*; D011956:Receptors, Cell Surface / Q000378:metabolism; D011971:Receptors, Immunologic / Q000502:physiology*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
D026503:Low Density Lipoprotein Receptor-Related Protein-1; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D015842:Serine Proteinase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D007371:Interferon-gamma; D000990:Antithrombin III