Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of pancreatic secretory trypsin inhibitor (PSTI) on cerulein-induced pancreatitis were studied in a rat model. Arg44 of PSTI was replaced by Ser using site-directed mutagenesis (R44S-PSTI). R44S-PSTI has a longer half-life than the natural form. Pancreatitis was induced by four intramuscular injections of cerulein (50 microgram/kg at 1 h intervals). Continuous intravenous infusion of R44S-PSTI began at a dose of 20 micrograms/kg/h 30 min before the first cerulein injection, and was completed 3 h after the last cerulein injection. Tumour necrosis factor (TNF-alpha) production by isolated peritoneal macrophages from rats with cerulein-induced pancreatitis increased following lipopolysaccharide stimulation, compared to control rats (P < 0.01). R44S-PSTI administration significantly decreased the TNF-alpha production by peritoneal macrophages from rats with cerulein-induced pancreatitis (P < 0.05). In addition, R44S-PSTI significantly reduced serum amylase activity (P < 0.01) and pancreatic wet weight after pancreatitis induction (P < 0.05). Histological examination revealed marked acinar cell vacuolization, interstitial oedema, and cellular infiltration in cerulein-induced pancreatitis, but a lesser degree of histological change in rats that were treated with R44S-PSTI. Prophylactic use of intravenous R44S-PSTI infusion may reduce the severity of acute pancreatitis either histologically or serologically.
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PMID:The protective effects of long-acting recombinant human pancreatic secretory trypsin inhibitor (R44S-PSTI) in a rat model of cerulein-induced pancreatitis. 867 1

Tumour necrosis factor-alpha (TNF-alpha), an important mediator in both immune and inflammation responses, is one of the major cytokines released by activated macrophages. The present study shows that, during macrophage activation, protein tyrosine phosphorylation of STAT1 alpha and ERK2 occurred as an immediate early signal, whereas maximum TNF-alpha mRNA transcription appeared at 3 hr, precursor TNF-alpha formation at 3 to 4 hr, and TNF-alpha release at 5 to 6 hr after stimulation of an RPMI-1640-based induction medium containing lipopolysaccharide (100 ng/ml), interferon-gamma (100 U/ml), and 0.5% bovine serum albumin. Herbimycin A, a tyrosine kinase inhibitor, suppresses protein tyrosine phosphorylation of STAT1 alpha and ERK2 and also blocks TNF-alpha production by resident peritoneal macrophages from BALB/c mice, suggesting a possible association between protein tyrosine phosphorylation of STAT1 alpha and ERK2 and macrophage activation resulting in TNF-alpha production.
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PMID:Dynamic production of tumour necrosis factor-alpha (TNF-alpha) messenger RNA, intracellular and extracellular TNF-alpha by murine macrophages and possible association with protein tyrosine phosphorylation of STAT1 alpha and ERK2 as an early signal. 867 7

Tumour necrosis factor-alpha (TNF) plays a pivotal role in acute and chronic inflammatory processes. It has been demonstrated that TNF is a mediator in inflammatory bowel disease. In the past different pharmacological approaches have been identified to suppress TNF synthesis in lipopolysaccharide-stimulated human mononuclear cells by cAMP-elevating agents. In the present study we examine whether TNF synthesis in the colon underlies similar regulatory mechanisms as in mononuclear cells. We therefore established a short-time organ culture of rat caecum. In this model we obtained maximal TNF formation of 159 pg/ml after a 7-h incubation period, as determined by L929 bioassay. The formation of bioactive TNF was confirmed by the application of neutralizing TNF antibody in the L929 bioassay and by immunodot blot. Lipopolysaccharide and pokeweed mitogen did not further enhance TNF synthesis. In contrast, TNF production was suppressed to 25% of control by 5 micrograms/ml hydrocortisone. Unexpectedly, the specific type IV phosphodiesterase inhibitor rolipram and cicaprost, a stable prostacyclin analogue, did not achieve significant suppression of TNF synthesis in this model. The present study defines an experimental model to investigate ex vivo TNF synthesis in rat colonic tissue. Applying this model, cAMP-elevating agents are identified as poor candidates for TNF-suppressing strategies in inflamed colon.
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PMID:Synthesis of tumour necrosis factor-alpha in tissue culture of rat caecum: lack of suppression by phosphodiesterase inhibitors and prostanoids. 885 58

Release and cellular contents of pro- and anti-inflammatory cytokines, neutrophilic elastase and secretory leukocyte proteinase inhibitor (SLPI) were measured with enzyme-linked immunosorbent assay in peripheral blood mono- and polymorphonuclear cells stimulated with preopsonized yeast cells or lipopolysaccharide. Tumour necrosis factor alpha (TNF alpha) was also measured with a bioassay. TNF alpha production and soluble TNF alpha receptor I (sTNF RI) were demonstrated in the environment of both cell populations. The bioassay indicated levels of TNF alpha far below those detected by ELISA. The overall secretion of cytokines and their inhibitors was found to favour an anti-inflammatory balance in the environment of the stimulated cells. The interleukin-1 receptor antagonist (IL1-ra), compared with interleukin-1 beta (IL-1 beta), dominated the secretions from both cell types with a 100- to 1000-fold excess respectively. Most of the translated IL-1 beta was not secreted but found associated with the cellular compartments. In contrast to lipopolysaccharide (LPS) stimulation, preopsonized yeast cells stimulated a massive release of elastase from neutrophil cells.
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PMID:Release of cytokines and proteases from human peripheral blood mononuclear and polymorphonuclear cells following phagocytosis and LPS stimulation. 886 69

Immunologically, the septic shock is a natural model of immunomediated vascular pathology where the interaction between cytokines and the endothelium mediates the syndrome and lethality. Tumour necrosis factor (TNF), a non-species-specific cytokine, has outstanding pleiotropic activities as an important mediator of the septic shock syndrome. In rabbits, passive immunization with anti-lipopolysaccharide (LPS) polyclonal antibodies prior to the intravenous (i.v.) injection of LPS inhibits the haemorrhagic necrotic lesion characteristic of the local Shwartzman reaction (an excellent localized in vivo correlate of the septic shock). Paradoxically, tested in an ex vivo assay (short-term whole human blood culture, stimulated with LPS), these antibodies mediated an increase in TNF production by mononuclear phagocytes and, in the rabbit model, they induced an increase in body temperature, as compared with the pre-immune reagent. Although anchoring of immune complexes containing LPS to receptors (Fc or C4b-C3b) on circulating monocytes may facilitate the access of LPS to these cells, access to localized, LPS-sensitized macrophages may be impaired. Consequently inhibition of the local Shwartzman reaction and increased TNF production in the ex vivo system were observed. Concordantly, the higher temperature in the passively immunized animals may be a consequence of a higher, immune complex-induced, systemic TNF production. These experimental results suggest that the use of anti-LPS immunoglobulins, as a potential immunotherapy for septic shock syndrome in vertebrates, may lead to increased TNF production, with adverse effects such as the pyrogenic.
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PMID:Immunomodulation of LPS ability to induce the local Shwartzman reaction. 897 35

Dialysable leucocyte extract (DLE), obtained from lysed leucocytes, provide clinical effectiveness in a broad spectrum of diseases. Tumour necrosis factor (TNF) is raised in AIDS patients leading to an increase in human immunodeficiency virus (HIV) replication in vitro [1,2], whereas progression to AIDS in asymptomatic HIV infected individuals is retarded under treatment with DLE. In the present study we tested the DLE effect in vitro on both TNF biological activity (cytotoxicity) in L929 cells and its induction by lipopolysaccharide (LPS) in human monocytes as well as in whole blood from healthy donors. When monocytic cells were simultaneously exposed to LPS and DLE during a period of 5 1/2 hours, the induction of TNF was strongly diminished. The same inhibitory effect of DLE on TNF induction was observed when LPS was added to the culture medium prior to DLE. No significant effect of DLE on TNF-mediated cytotoxicity, even in the presence of the highest concentrations of DLE tested, was detected. DLE treatment of whole human blood regulates responses to LPS: simultaneous in vitro exposure to endotoxin provokes a remarkable decrease (4- and 1.6-fold) of TNF release. In pre-incubation experiments, TNF production was largely reduced or completed abrogated. These results could, in part, explain the in vivo observed effect, when under treatment with this extract, the progression to AIDS of HIV-infected individuals was retarded. The results suggest that "natural' substances like DLE may be important immunomodulators in inflammatory diseases.
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PMID:Dialysable leucocyte extract (DLE) reduces lipopolysaccharide-induced tumour necrosis factor secretion in human leucocytes. 899 76

We investigated time-related productions of certain cytokines in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, a murine macrophage cell line, by enzyme-linked immunosorbent assay. Macrophage inflammatory protein-2 (MIP-2) levels became detectable after 2 h and markedly increased over the first 8 h. Thereafter, this level remained at the same level between 10 and 16 h, and then increased again until 24 h, showing a tendency of biphasic pattern. Tumour necrosis factor (TNF)-alpha was detectable at 2 h and then increased sharply until 6 h at which it attained its peak. A low but recognizable level of interleukin (IL)-1alpha/beta was also detectable. When the inhibitory effect of ferulic acid (FA), an active component of the Rhizoma of Cimicifuga sp. used frequently as anti-inflammatory drug in Japanese Oriental medicines, was compared with that of dexamethasone (DX) on MIP-2 and TNF-alpha productions in response to LPS, both FA and DX could reduce the production of these cytokines in a dose-dependent manner. Concerning TNF-alpha, however, the inhibitory effect of FA was very weak compared with that of DX. In addition, FA as well as DX reduced MIP-2 production induced by TNF-alpha. These data suggest that MIP-2 might be induced by a direct effect of LPS and in part indirect one via initial induction of other cytokines such as TNF-alpha, leading a tendency of biphasic pattern. Comparing DX, FA is considered to be a novel and unique drug inhibiting MIP-2 production more selectively.
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PMID:Inhibitory effect of ferulic acid on macrophage inflammatory protein-2 production in a murine macrophage cell line, RAW264.7. 911 32

Imiquimod, S-27609 and S-28463 are imidazoquinolines known to have antiviral and antitumour properties mediated by the induction of cytokines, in particular interferon alpha (IFN-alpha). This study evaluated these compounds for their ability to induce cytokines and cytokine specific messenger RNAs (mRNA) in cynomologus monkeys (Macaca fascicularis). Peripheral blood mononuclear cell (PBMC) cultures from monkeys produced IFN, interleukin 1beta (IL-1beta), IL-6 and IL-8 after treatment with imiquimod, S-27609 and S-28463. Tumour necrosis factor alpha (TNF-alpha) was also increased in cultures stimulated with S-27609 or S-28463. Monkey PBMCs stimulated with imiquimod, S-27609 and S-28463 showed increased mRNA levels of IFN-alpha, IL-1alpha, IL-6 and the IFN inducible protein, MxA above those seen in untreated cultures. S-27609 and S-28463 also had higher TNF-alpha mRNA expression than cultures not receiving drugs. When compared to lipopolysaccharide (LPS), S-27609 was less effective at inducing IL-1beta, IL-6, IL-8 and TNF-alpha but induced higher concentrations of IFN. Similar results were seen when evaluating cytokine mRNA levels. Upon oral administration to monkeys, S-28463 stimulated a dose-dependent increase in serum concentrations of IFN, TNF-alpha, IL-1 receptor antagonist (IL-1Ra) and IL-6, while imiquimod induced increases in IFN and IL-1Ra concentrations. Finally, skin biopsies from monkeys treated topically with S-28463 had increases over baseline in mRNA for IFN-alpha, IL-1alpha, IL-6 and MxA protein. The data show that imidazoquinolines induce cytokines and cytokine specific mRNA in cynomolgus monkeys. These results demonstrate the usefulness of human amplimers and human ELISAs in the detection of cytokine specific mRNAs and proteins in cynomolgus monkeys.
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PMID:Induction of cytokines in cynomolgus monkeys by the immune response modifiers, imiquimod, S-27609 and S-28463. 936 44

Tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) are pro-inflammatory cytokines that play an important role in severe infections, whereas IL-1 receptor antagonist (IL-1ra) and IL-10 are anti-inflammatory cytokines that counteract their effects. Chlorpromazine and dexamethasone protect mice against lethal endotoxaemia by decreasing circulating concentrations of TNF-alpha and IL-1 beta. We investigated whether administration of chlorpromazine or dexamethasone to human volunteers is able to modulate the lipopolysaccharide (LPS)-stimulated cytokine production capacity in whole blood. Blood samples were taken before and several time-points after medication. Circulating cytokine concentrations were low in all samples. LPS-induced TNF-alpha and IL-1 beta production in whole blood was inhibited by dexamethasone treatment, while chlorpromazine had no effect. When peripheral blood mononuclear cells were stimulated in vitro with LPS, the addition of chlorpromazine (1-100 ng/ml) had no modulatory action on TNF-alpha, IL-1 beta, IL-1ra or IL-10 synthesis. The chlorpromazine concentrations measured in circulation of volunteers were eight to 40 times lower than the concentrations shown to be effective in mice. In conclusion, chlorpromazine inhibits TNF-alpha and IL-1 beta production in mice at concentrations that cannot be reached in humans, thus precluding its usage in clinical anti-cytokine strategies. In contrast, dexamethasone is an effective inhibitor of pro-inflammatory cytokine production.
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PMID:The effects of dexamethasone and chlorpromazine on tumour necrosis factor-alpha, interleukin-1 beta, interleukin-1 receptor antagonist and interleukin-10 in human volunteers. 937 93

Tumour necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) are potent inflammatory cytokines produced by osteoblasts and whose contribution to bone loss occurring in oestrogen deficiency is well documented. Calcitonin gene-related peptide (CGRP) is a neuropeptide abundantly concentrated in sensory nerve endings innervating bone metaphyses and periosteum suggesting that it controls bone homeostasis locally. Since CGRP was shown to inhibit TNF-alpha production by T cells and stimulate IL-6 expression by fibroblasts, this study was designed to investigate whether CGRP regulated TNF-alpha and IL-6 production by osteoblasts. We show that CGRP inhibits the production of TNF-alpha by both lipopolysaccharide (LPS)- and IL-1-stimulated fetal rat osteoblasts. Like CGRP, the cAMP agonists prostaglandin E2 (PGE2), dibutyryl cAMP (Bt2cAMP) and forskolin inhibit TNF-alpha production by osteoblasts. Exposure of osteoblasts to a high dose of phorbol myristoyl acetate (PMA) to deplete PKC activity abolished CGRP-mediated TNF-alpha suppression. In contrast with its potent inhibition of TNF-alpha production, we show that CGRP is a weak inducer of IL-6 when compared to PGE2, Bt2cAMP and forskolin. However, in presence of isobutylmethylxanthine (IBMX) CGRP stimulates the production of IL-6. Collectively, these data suggest that the inhibition of TNF-alpha CGRP is cAMP dependent and PMA sensitive and that the concentration of intracellular cAMP may be a regulatory mechanism for IL-6 expression in osteoblasts.
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PMID:The neuropeptide calcitonin gene-related peptide inhibits TNF-alpha but poorly induces IL-6 production by fetal rat osteoblasts. 941 11


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