Macrophage endothelial nitric-oxide synthase autoregulates cellular activation and pro-inflammatory protein expression.
Expression of inducible nitric-oxide (NO) synthase (iNOS) and "high-output" production of NO by macrophages mediates many cytotoxic actions of these immune cells. However, macrophages have also been shown to express a constitutive NOS isoform, the function of which remains obscure. Herein, bone marrow-derived macrophages (BMDMØs) from wild-type and endothelial NOS (eNOS) knock-out (KO) mice have been used to assess the role of this constitutive NOS isoform in the regulation of macrophage activation. BMDMØs from eNOS KO animals exhibited reduced nuclear factor-kappaB activity, iNOS expression, and NO production after exposure to lipopolysaccharide (LPS) as compared with cells derived from wild-type mice. Soluble guanylate cyclase (sGC) was identified in BMDMØs at a mRNA and protein level, and activation of cells with LPS resulted in accumulation of cyclic GMP. Moreover, the novel non-NO-based sGC activator, BAY 41-2272, enhanced BMDMØ activation in response to LPS, and the sGC inhibitor 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one attenuated activation. These observations provide the first demonstration of a pathophysiological role for macrophage eNOS in regulating cellular activation and suggest that NO derived from this constitutive NOS isoform, in part via activation of sGC, is likely to play a pivotal role in the initiation of an inflammatory response.
Department of Molecular and Medical Pharmacology, UCLA School of Medicine, Los Angeles, California 90095, USA.
Linda
L
Connelly
Aaron T
AT
Jacobs
Miriam
M
Palacios-Callender
Salvador
S
Moncada
Adrian J
AJ
Hobbs
D000818:Animals; D006152:Cyclic GMP / Q000096:biosynthesis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D006706:Homeostasis; D066298:In Vitro Techniques; D007249:Inflammation / Q000209:etiology; D018836:Inflammation Mediators / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D010069:Oxadiazoles / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012995:Solubility
C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; C423582:3-(4-Amino-5-cyclopropylpyrimidine-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo(3,4-b)pyridine; D004791:Enzyme Inhibitors; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D016328:NF-kappa B; D010069:Oxadiazoles; D011720:Pyrazoles; D011725:Pyridines; D011810:Quinoxalines; D012333:RNA, Messenger; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse; D006162:Guanylate Cyclase; D006152:Cyclic GMP