title: NF-kappa B regulation by I kappa B kinase-2 in rheumatoid arthritis synoviocytes.
abstract: IkappaB kinase-1 and IkappaB kinase-2 (IKK1 and IKK2; also called IKKalpha and IKKbeta, respectively) are part of the signal complex that regulates NF-kappaB activity in many cell types, including fibroblast-like synoviocytes (FLS). We determined which of these two kinases is responsible for cytokine-induced NF-kappaB activation in synoviocytes and assessed the functional consequences of IKK1 or IKK2 overexpression and inhibition. FLS were infected with adenovirus constructs encoding either wild-type (wt) IKK1 or IKK2, the dominant negative (dn) mutant of both kinases, or a control construct encoding green fluorescence protein. Analysis of the NF-kappaB pathway revealed that cytokine-induced IKK activation, IkappaB degradation, and NF-kappaB activation was prevented in cells expressing the IKK2 dn mutant, whereas baseline NF-kappaB activity was increased by IKK2 wt. In addition, synthesis of IL-6 and IL-8, as well as expression of ICAM-1 and collagenase, was only increased by IKK2 wt, and their cytokine-induced production was abrogated by IKK2 dn mutant. However, the IKK1 dn mutant did not inhibit cytokine-mediated activation of NF-kappaB or any of the functional assays. These data indicate that IKK2 is the key convergence pathway for cytokine-induced NF-kappaB activation. Furthermore, IKK2 regulates adhesion molecule, matrix metalloproteinase, and cytokine production in FLS.
authors.affiliation: Division of Rheumatology, Allergy and Immunology, University of California San Diego School of Medicine, La Jolla, CA, USA.
authors.forename: K
authors.initials: K
authors.lastname: Aupperle
authors.forename: B
authors.initials: B
authors.lastname: Bennett
authors.forename: Z
authors.initials: Z
authors.lastname: Han
authors.forename: D
authors.initials: D
authors.lastname: Boyle
authors.forename: A
authors.initials: A
authors.lastname: Manning
authors.forename: G
authors.initials: G
authors.lastname: Firestein
mesh_terms: D000256:Adenoviridae / Q000201:enzymology / Q000235:genetics; D001172:Arthritis, Rheumatoid / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D002460:Cell Line; D002478:Cells, Cultured; D017364:Collagenases / Q000096:biosynthesis / Q000235:genetics; D005347:Fibroblasts / Q000201:enzymology / Q000473:pathology; D005822:Genetic Vectors / Q000138:chemical synthesis / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051550:I-kappa B Kinase; D020672:I-kappa B Proteins / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D013583:Synovial Membrane / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D020672:I-kappa B Proteins; D007375:Interleukin-1; D015850:Interleukin-6; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; D017364:Collagenases