Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activity of the transcription factor NF-kappaB is tightly regulated by the inhibitory molecule IkappaBalpha. Upon stimulation, IkappaBalpha is rapidly degraded and NF-kappaB translocates to the nucleus to induce gene expression. The IkappaBalpha degradation is preceded by phosphorylation, suggesting that this event plays a role in the activation of NF-kappaB. In this study, we have mutated three potential phosphorylation sites in porcine IkappaBalpha and found that expression of the Ser32 mutant of IkappaBalpha (IS32A), but not Tyr42 or Ser262 mutants or wild-type IkappaBalpha, blocked the activation of NF-kappaB by TNF-alpha. These results suggest that the Ser32 residue, a potential casein kinase II phosphorylation site, is critical for NF-kappaB activation.
Mol Immunol 1996 Jan
PMID:Inhibition of NF-kappaB activation by a dominant-negative mutant of IkappaBalpha. 860 24

(2E)-3-[5-(2,3-Dimethoxy-6-methyl-1,4-benzoquinoyl)]-2-nonyl-2- propenoic acid (E3330), is a novel agent with hepatoprotective activity. We report the effect of E3330 on transcriptional activation of tumor necrosis factor (TNF)-alpha gene and on nuclear factor (NF)-kappa B activation. Nuclear run-on experiments showed that E3330 decreases transcriptional activation of TNF-alpha gene induced by lipopolysaccharide (LPS) stimulation in human peripheral monocytes. To investigate the inhibitory mechanisms, we constructed a secreted-type placental alkaline phosphatase (PLAP) reporter gene whose transcription is controlled by a 1.4-kb human TNF-alpha promoter. A stable transformant of the PLAP reporter gene derived from human monocytic cell line showed very little activity on the promoter before stimulation, whereas LPS stimulation led to a dramatic increase in PLAP activity. E3330 inhibited this induced promoter activity in a dose-dependent manner. There are four putative NF-kappa B binding sites (kappa B-1, kappa B-2, kappa B-3, kappa B-4) in human TNF-alpha promoter. By using mutated promoter-PLAP plasmids, we established that these NF-kappa B sites were necessary for induction of TNF-alpha transcription on stimulation with LPS. A gel retardation experiment with synthetic double-stranded oligonucleotides showed that activated NF-kappa B consisting of p50/p65 heterodimer bound to all four putative NF-kappa B DNA probes, suggesting that all four putative NF-kappa B recognition sites play an important role in inducible TNF-alpha expression. E3330 decreased activated NF-kappa B in nuclei, suggesting that E3330 inhibits NF-kappa B activation and/or translocation of the nuclei. Western blotting analysis with anti-I kappa B-alpha antibody indicated that E3330 inhibited degradation of I kappa B-alpha, which is an inhibitory protein of NF-kappa B, in LPS-stimulated monocytes. E3330 may suppress the production of active oxygen species serving as common messengers to activate NF-kappa B.
Mol Pharmacol 1996 May
PMID:Inhibitory effect of E3330, a novel quinone derivative able to suppress tumor necrosis factor-alpha generation, on activation of nuclear factor-kappa B. 862 36

Our previous work demonstrated that hypoxia decreases transcription of the human prostaglandin H synthase-2 (PGHS-2) gene during exposure to lipopolysaccharide (LPS), resulting in decreased prostaglandin E2 (PGE2) synthesis (J. Biol. Chem. 269:32979-32984, 1994). Because PGE2 is reported to inhibit interleukin 1 (IL-1) and tumor necrosis factor (TNF), it is likely that hypoxia, through changes in PGE2, will alter IL-1 and TNF release from the human alveolar macrophage. In addition, like PGHS-2, the TNF and IL-1 promoters contain oxidant-sensitive elements which might be altered by hypoxia. Therefore, we hypothesized that LPS-induced release of TNF and IL-1 would be altered by hypoxia. To test this, human alveolar macrophages were cultured for 24 h with 0 to 1 microgram/ml LPS in a room-air incubator with 5% CO2 or a hypoxia incubator continuously perfused with 5% CO2/95% N2 (O2 < 0.05%). With room air, LPS increased IL-1 beta mRNA and increased IL-1 beta protein release into the culture medium in a dose-dependent manner. Hypoxia increased the LPS-stimulated release of IL-1 beta 30% above that of room-air controls. However, immunoblots showed that hypoxia caused no change in intracellular IL-1 beta compared with room-air controls. There was also no change in LPS-induced IL-1 beta message with hypoxia. The inhibitor of IL-1, IL-1RA, was apparently decreased by hypoxia, but this decrease was not statistically significant. TNF-alpha mRNA and release of protein also increased during LPS exposure in room air. Hypoxia markedly increased LPS-induced TNF-alpha message and release of TNF-alpha compared with LPS-exposed room-air controls. Consistent with our prior observations, hypoxia decreased LPS-induced PGHS-2 message and protein, and also the PGHS-2 product, PGE2. Because PGE2 is reported to inhibit the expression of IL-1 and TNF genes, we inhibited PGE2 synthesis with indomethacin during culture in room air; the result was an increase in the release of IL-1 and TNF. In additional studies, adding PGE2 inhibited TNF release from the hypoxia cells to values near those of room-air controls. In summary, hypoxia increases the release of the cytokines IL-1 beta and TNF-alpha. This increase may be due to decreased PGE2 synthesis during hypoxia. These results demonstrate that the response of the human alveolar macrophage to hypoxia is complex. Hypoxia increases the LPS-stimulated release of the inflammatory cytokines IL-1 and TNF, whereas synthesis of PGHS-2, which generates the anti-inflammatory prostaglandin PGE2 is decreased.
Am J Respir Cell Mol Biol 1996 Feb
PMID:Effect of hypoxia on release of IL-1 and TNF by human alveolar macrophages. 863 Feb 67

A specific tumour necrosis factor alpha ribozyme (TNF-alpha-Rz) binding activity has been purified and identified by N-terminal microsequencing as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The purified protein as well as commercial GAPDH binds tightly to TNF-alpha ribozyme compared to a variety of other ribozymes and RNAs. Binding of GAPDH to the TNF-alpha-Rz and its derivatives was inhibited by NAD+ and ATP, suggesting that the GAPDH Rossmann fold structure is a part of the ribozyme binding site. Interestingly, GAPDH increased the in vitro cleavage rates of hammerhead ribozymes by up to 25-fold, while no significant stimulation was observed with the lactate dehydrogenase (LDH). This effect was found to be due to the unfolding activity of GAPDH. In fact, pulse-chase experiments demonstrate directly that GAPDH has the capacity to accelerate the ribozyme/substrate association, especially of ribozymes and/or substrates whose predicted secondary structure might interfere with the association step. Under our conditions, the presumed unfolding activity of GAPDH also enhances the turnover of ribozymes by increasing the rate of product dissociation, although only for short cleavage products. Longer duplexes required more incubation time to dissociate. In vitro non-specific interaction of the GAPDH with hammerhead ribozymes and RNA substrates was found to be adequate for the cleavage enhancement effect to occur. However, an analysis of the ability of various prototypical ribozymes to inhibit the expression of interleukin-2 suggests that the addition of a sequence having a high affinity for GAPDH improves the efficacy of ribozymes in the cells. Thus the characterization of cellular proteins with unfolding activity, which specifically bind to hammerhead ribozyme, should facilitate the design of a more effective ribozyme in vivo.
J Mol Biol 1996 Apr 12
PMID:Enhancement of hammerhead ribozyme catalysis by glyceraldehyde-3-phosphate dehydrogenase. 863 81

Mice were exposed to pure oxygen for various times to explore the pulmonary platelet trapping associated with alveolar damage, its mechanism, and its role in the lesions. Platelet sequestration, evaluated by electron microscopy and by injection of radiolabeled platelets, was detectable after 72 h and reached a maximum after 96 h of exposure (i.e., shortly before death). Circulating platelets (analyzed by Facscan) showed some increase in the expression of CD11a and CD62, but little change in CD31 and CD61. Both platelet activation and lung sequestration were dependent on TNF-alpha, since antibody against TNF-alpha reduced the expression of CD11a on circulating platelets and their sequestration in the lung. Lung platelet sequestration was also decreased by anti-CD11a MoAb. Northern blot analysis of lung mRNA isolated at 96 h of oxygen exposure revealed a 7-fold increase in CD54 (intercellular adhesion molecule-1 [ICAM-1]) and a 2.5-fold increase in TNF-alpha mRNAs respectively. These results demonstrate that the platelet pulmonary trapping induced by hyperoxia is dependent upon TNF-alpha and the CD11a-CD54 adhesion molecules. However, platelet trapping does not appear to play an important pathogenic role in acute oxygen injury, since treatments that decrease trapping (anti-TNF-alpha, anti-CD11a, or antibody-induced thrombocytopenia) did not markedly attenuate the alveolar damage.
Am J Respir Cell Mol Biol 1996 Jul
PMID:Hyperoxia induces platelet activation and lung sequestration: an event dependent on tumor necrosis factor-alpha and CD11a. 867 14

A central factor in the pathogenesis of inflammatory and fibrotic lung disease (adult respiratory distress syndrome, sarcoidosis, idiopathic pulmonary fibrosis) is the locally elevated number of alveolar macrophages (AM). An elevation in the production rate of AM, chemoattraction and differentiation of monocytes, or a diminution in the death rate might be underlying mechanisms. The aim of the present study was to investigate the modulatory role of endotoxin and cytokines on the death rate of human AM. Lipopolysaccharide (LPS) treatment resulted in a 4-fold increase (7.6 to 30.2%) of AM death. AM death was apoptotic as assessed by in situ DNA end labeling (ISDE), transmission electron microscopy, DNA gel electrophoresis, fluorometry of fragmented DNA, and an ELISA specific for histone-associated DNA fragments. Among the different bacterial cell wall components tested, LPS was the only inducer of apoptosis in human AM. None of the tested cytokines (interleukin-1 beta [IL-1 beta], IL-4, IL-6, IL-10, tumor necrosis factor-alpha [TNF-alpha], transforming growth factor-beta 2 [TGF-beta 2], interferon-gamma [IFN-gamma], macrophage colony-stimulating factor [M-CSF], granulocyte colony-stimulating factor [G-CSF], and granulocyte-macrophage colony-stimulating factor [GM-CSF]) was capable of enhancing the spontaneous rate of apoptosis. However, LPS-induced apoptosis was significantly enhanced by the macrophage-activating cytokine IFN-gamma, and reduced by the macrophage-deactivating cytokines IL-4, IL-10, and TGF-beta.
Am J Respir Cell Mol Biol 1996 Jul
PMID:Apoptosis in human alveolar macrophages is induced by endotoxin and is modulated by cytokines. 867 23

We investigated the effect of adenosine 3', 5'-cyclic monophosphate (cAMP) on inducible nitric oxide synthase (iNOS) expression in cultured neonatal rat cardiac myocytes. Incubation of cardiac myocytes for 24 h with interleukin-1 beta (IL-1 beta) caused a significant increase in the production of nitrite, a stable metabolite of nitric oxide. Dibutyl cAMP (db-cAMP) significantly augmented nitrite production by IL-1 beta-stimulated, but not by unstimulated cells, in a dose-dependent manner. db-cAMP also dose dependently increased nitrite production by tumor necrosis factor-alpha(TNF-alpha)-stimulated cells. Simultaneous incubation with NG-monomethyl-L-arginine completely inhibited the effect of db-cAMP on nitrite production. cAMP-induced nitrite production by cytokine-stimulated cells was accompanied by increased iNOS mRNA accumulation. The synergistic effect of cAMP on IL-1 beta-induced nitrite accumulation was mimicked by cAMP-generating agonists forskolin and isoproterenol. These results indicate that cAMP upregulates cytokine-induced iNOS expression in cardiac myocytes.
J Mol Cell Cardiol 1996 Apr
PMID:Cyclic AMP augments cytokine-stimulated nitric oxide synthesis in rat cardiac myocytes. 873 6

An experimental acute liver injury model can be produced by the injection of bacterial lipopolysaccharide (LPS) into Propionibacterium acnes (P. acnes) pretreated rats. The massive liver cell necrosis is estimated by elevation of serum transaminase activities. In this study, we produced this necrosis in an in vitro model by using primary co-cultured rat liver cells. A novel method for the preparation of spheroids consisting of P. acnes pretreated parenchymal and nonparenchymal liver cells has been successfully developed quickly by the rotary culture system within 24 hr although it takes 7 days to form the spheroid using a collagen-conjugated thermo-responsive polymer such as a cell substratum. Clear elevations of transaminase activities, TNF-alpha and CINC-1/gro/KC leaked from these spheroids into the medium caused by the exposure of 10 microgram/ml LPS for 48 hr were observed. These results suggest that this rotary co-culture system of rat liver cells is a useful model as an alternative to animal tests for fulminant hepatitis.
Res Commun Mol Pathol Pharmacol 1995 Dec
PMID:Rapid formation of multicellular spheroids composed of Propionibacterium acnes pretreated adult rat liver cells by rotary culture and their immunological properties. 874 84

Local production in tubular cells of complement has been shown to occur in several kidney diseases by in situ hybridization, but the regulation at the local site during an inflammation is still unknown. In the present study, we demonstrate that human proximal tubular epithelial cells (PTEC) are able to produce complement components C3 and Factor B under non-stimulated conditions in vitro. The basal production of both was increased by 0.5 ng/ml interleukin-1 alpha (IL-1 alpha) for C3: from 95.5 +/- 4.0 ng/10(6) cells to 416.5 +/- 4.9 ng/10(6), and for Factor B: from 271 +/- 7.0 ng/10(6) cells to 457.5 +/- 7.0 ng/10(6) cells. In contrast cytokines such as TNF-alpha, IFN-gamma, IL-10 and IL-15 had no detectable effect. The upregulation by IL-1 alpha was dose- and time-dependent. The response to IL-1 alpha was shown to be mediated via the IL-1 receptor, as the addition of recombinant interleukin-1 receptor antagonist inhibited the IL-1 alpha induced complement production by more than 80%. IL-1 alpha enhanced mRNA expression of both C3 and Factor B as demonstrated by RT-PCR and dot-blot analysis. This indicated that IL-1 alpha upregulated the expression of the C3 and Factor B at the transcriptional level. We hypothesize that in vivo the production of C3 and Factor B at the local site during an inflammatory response in the kidney may be regulated by IL-1 alpha produced by inflammatory cells.
Mol Immunol 1996 Jul
PMID:Interleukin-1 alpha enhances the biosynthesis of complement C3 and factor B by human kidney proximal tubular epithelial cells in vitro. 884 16

The effect of nitric oxide on the lipopolysaccharide (LPS)-induced cytokine production by alveolar macrophages was studied. When alveolar macrophages were cultured, substantial amounts of interleukin-1(IL-1), interleukin-6 (IL-6), tumor necrosis factor alpha(TNF-alpha), and nitric oxide are produced upon stimulation with LPS. Inhibition of the nitric oxide production by the L-arginine analogue N(G)-monomethyl-L-arginine (NMMA), resulted in an increase of IL-1(beta) and IL-6, whereas the TNF-alpha concentrations remained unchanged, suggesting specific inhibitory effects of nitric oxide on the LPS-stimulated cytokine production by alveolar macrophages. The observed cytokine-modulation properties of nitric oxide did not result from cytotoxic actions of the oxidation of L-arginine on macrophages, since nitric oxide synthesis did not affect the viability of the alveolar macrophages. Conversely the nitric oxide donor S-nitroso-N-acetyl-D, L-penicillamine (SNAP) induced dose-dependent inhibition of IL-1 production in LPS-stimulated alveolar macrophages in which endogenous nitric oxide production was blocked. The results indicate that nitric oxide can affect the LPS-induced IL-1beta and IL-6 secretion by alveolar macrophages in an autoregulatory way and are discussed in view of the important physiologic consequences this autoregulation by nitric acid oxide may have.
Am J Respir Cell Mol Biol 1996 Mar
PMID:Alveolar macrophages autoregulate IL-1 and IL-6 production by endogenous nitric oxide. 884 78


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