Mitogen-activated protein kinases mediate activator protein-1-dependent human inducible nitric-oxide synthase promoter activation.
Inducible nitric-oxide synthase (iNOS) is an important signaling protein involved in the regulation of biological processes (e.g. vasodilation, inflammation) and is subject to transcriptional regulation by cytokines and lipopolysaccharide (LPS). Full activation of the human iNOS (hiNOS) promoter by cytokines (i.e., tumor necrosis factor-alpha, interleukin-1beta, interferon-gamma (IFN-gamma)) required downstream and upstream nuclear factor-kappaB (-115, -8283) and activator protein-1 (AP-1) (-5115, -5301) transcription factor binding sites. Human lung epithelial (A549) cells were transiently transfected with luciferase reporter plasmids containing an 8.3-kilobase human iNOS promoter to examine the molecular signaling events necessary for hiNOS transcriptional activation. The combination of LPS and IFN-gamma, but neither alone, increased hiNOS promoter activity 28-fold, in a reaction requiring two critical AP-1 (JunD-Fra-2) promoter binding sites. Mitogen-activated protein kinases (MAPKs) were assessed as potential activators of AP-1 and the hiNOS promoter. Both pharmacological and molecular inhibitors of the extracellular signal-related kinase (ERK) and p38 pathways reduced cytokine mixture (CM)- and LPS/IFN-gamma-induced promoter activation. By gel retardation analysis, the addition of MAP/ERK kinase-1 and p38 inhibitors significantly diminished AP-1 binding in both CM- and LPS/IFN-gamma-stimulated cells. Thus, p38- and ERK-dependent pathways, through effects on the AP-1 complex, activate the hiNOS promoter in cells stimulated with CM or LPS/IFN-gamma.
Kristof
A S
AS
Pulmonary-Critical Care Medicine Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1434, USA. kristofa@nih.gov
Marks-Konczalik
J
J
Moss
J
J
D001665:Binding Sites; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D053614:Janus Kinase 2; D008070:Lipopolysaccharides / Q000494:pharmacology; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics*; D052247:Nitric Oxide Synthase Type II; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D011518:Proto-Oncogene Proteins; D011725:Pyridines / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000502:physiology*; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases
D005419:Flavonoids; D007093:Imidazoles; D008070:Lipopolysaccharides; D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D011725:Pyridines; D018808:Transcription Factor AP-1; D007371:Interferon-gamma; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D017346:Protein Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one