title: Restraint of proinflammatory cytokine biosynthesis by mitogen-activated protein kinase phosphatase-1 in lipopolysaccharide-stimulated macrophages.
abstract: Exposure of macrophages to LPS elicits the production of proinflammatory cytokines, such as TNF-alpha, through complex signaling mechanisms. Mitogen-activated protein (MAP) kinases play a critical role in this process. In the present study, we have addressed the role of MAP kinase phosphatase-1 (MKP-1) in regulating proinflammatory cytokine production using RAW264.7 macrophages. Analysis of MAP kinase activity revealed a transient activation of c-Jun N-terminal kinase (JNK) and p38 after LPS stimulation. Interestingly, MKP-1 was induced concurrently with the inactivation of JNK and p38, whereas blocking MKP-1 induction by triptolide prevented this inactivation. Ectopic expression of MKP-1 accelerated JNK and p38 inactivation and substantially inhibited the production of TNF-alpha and IL-6. Induction of MKP-1 by LPS was found to be extracellular signal-regulated kinase dependent and involved enhanced gene expression and increased protein stability. Finally, MKP-1 expression was also induced by glucocorticoids as well as cholera toxin B subunit, an agent capable of preventing autoimmune diseases in animal models. These findings highlight MKP-1 as a critical negative regulator of the macrophage inflammatory response, underscoring its premise as a potential target for developing novel anti-inflammatory drugs.
authors.affiliation: Stress Signaling Unit, Laboratory of Cellular and Molecular Biology, National Institute on Aging, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA.
authors.forename: Peili
authors.initials: P
authors.lastname: Chen
authors.forename: Ji
authors.initials: J
authors.lastname: Li
authors.forename: Janice
authors.initials: J
authors.lastname: Barnes
authors.forename: Gertrude C
authors.initials: GC
authors.lastname: Kokkonen
authors.forename: John C
authors.initials: JC
authors.lastname: Lee
authors.forename: Yusen
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis*; D003907:Dexamethasone / Q000494:pharmacology; D004224:Diterpenes / Q000494:pharmacology; D054638:Dual Specificity Phosphatase 1; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability / Q000187:drug effects; D004852:Epoxy Compounds; D015870:Gene Expression; D017874:Immediate-Early Proteins / Q000096:biosynthesis* / Q000235:genetics; D018836:Inflammation Mediators / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases; D008070:Lipopolysaccharides / Q000633:toxicity; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D010616:Phenanthrenes; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D018797:Cell Cycle Proteins; D016207:Cytokines; D004224:Diterpenes; D004791:Enzyme Inhibitors; D004852:Epoxy Compounds; D017874:Immediate-Early Proteins; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D010616:Phenanthrenes; D012333:RNA, Messenger; C001899:triptolide; D003907:Dexamethasone; D002772:Cholera Toxin; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D054638:Dual Specificity Phosphatase 1; C517020:Dusp1 protein, mouse; D017027:Protein Tyrosine Phosphatases