UNIPROT:P43026 - FACTA Search

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)

Tumor necrosis factor alpha (TNFalpha), an early cytokine produced by activated macrophages, plays an essential role in normal and pathological inflammatory reactions. The excessive production of TNFalpha is prevented by the so-called "macrophage-deactivating factors." This study examines the role of two structurally related neuropeptides, the vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating peptide (PACAP), as inhibitors of TNFalpha. Both VIP and PACAP inhibit TNFalpha production from lipopolysaccharide-stimulated RAW 246.7 cells in a dose- and time-dependent manner. Although the activated cells express mRNA for all three VIP/PACAP receptors, agonist and antagonist studies indicate that the major receptor involved is VIP1R. VIP/PACAP inhibit TNFalpha gene expression by affecting both NF-kB binding and the composition of the cAMP responsive element binding complex (CREB/c-Jun). Two transduction pathways, a cAMP-dependent and a cAMP-independent pathway, are involved in the inhibition of TNFalpha gene expression and appear to differentially regulate the transcriptional factors involved. Because TNFalpha plays a central role in various inflammatory diseases such as endotoxic shock, multiple sclerosis, cerebral malaria, and various autoimmune conditions, the down-regulatory effect of VIP/PACAP may have a significant therapeutic potential.
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PMID:Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit tumor necrosis factor alpha transcriptional activation by regulating nuclear factor-kB and cAMP response element-binding protein/c-Jun. 981 54

Tyrosine kinase blockers from the AG 126/AG-556 tyrphostin family are shown to inhibit the lipopolysaccharide (LPS)-induced production of tumor necrosis factor alpha (TNFalpha), nitric oxide (NO), and prostaglandin E2 (PGE2) in primary rat astrocytes cultures. The tyrphostin AG-556 which was previously shown to be effective against sepsis in mice and dogs also show excellent efficacy in inhibiting experimental autoimmune encephalomyelitis (EAE) in mice. AG-556 does not block the activation of JNK/SAPK and of p38/HOG and therefore seems to act at a target down stream to these kinases which is activated in stress or at a target on an obligatory parallel pathway. These findings together with previous results showing inhibition of sepsis in mice and dogs suggest that protein tyrosine kinase (PTK) blockers of the AG-556 family may be considered in the management of human autoimmune disorders such as multiple sclerosis (MS).
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PMID:Suppression of experimental autoimmune encephalomyelitis by tyrphostin AG-556. 987 84

A major question relevant to the initiation and progression of inflammation and autoimmune processes within the central nervous system (CNS) is whether resident microglia or only infiltrating macrophage can productively interact with T-cells that enter the CNS either actively through extravasation or passively through defects in the blood brain barrier (BBB). We isolated microglia and macrophage from the brains of healthy adult mice and transgenic mice that displayed many features of multiple sclerosis and HIV leukoencephalopathy due to the astrocytic expression of interleukin (IL)-3 and compared their antigen-presenting cell (APC) functions. We found that unactivated microglia isolated from healthy nontransgenic mice and activated microglia isolated from transgenic siblings are relatively weak stimulators of naive T-cell proliferation compared to macrophage populations. The APC function of activated, but not unactivated, microglia could be increased by treatment acutely with lipopolysaccharide (LPS)/interferon gamma (IFN-gamma). However, this treatment also induced the apparent production of prostaglandins, which reduced T-cell proliferation when indomethacin was absent from the assay cultures. Strikingly, even in the absence of stimulated T-cell proliferation, both unactivated and activated microglia stimulated the differentiation of naive T-cells into Th1 effector cells, although neither microglial population was a more effective inducer than macrophages or splenic APCs. Thus, while microglia are clearly capable of productively interacting with naive T-cells, macrophages have a more robust APC function.
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PMID:Microglia stimulate naive T-cell differentiation without stimulating T-cell proliferation. 989 Apr 41

There is mounting evidence that inflammation and associated excitotoxicity may play important roles in various neurodegenerative disorders, such as bacterial infections, Alzheimer's disease, AIDS dementia, and multiple sclerosis. The immunogen E. coli lipopolysaccharide (LPS, endotoxin) has been widely used to stimulate immune/inflammatory responses both systemically and in the CNS. Here, we show that exposure of parietal cortical slices from adult rats to LPS triggered very rapid (<2.5 min) and sustained releases of the neurotransmitters glutamate and noradrenaline, and of the neuromodulator adenosine. The responses to LPS declined rapidly following removal of the LPS and exhibited no tachyphylaxis to repeated exposures to LPS. The detoxified form of LPS had no effect. LPS-evoked release of [3H]noradrenaline, but not of glutamate or adenosine, appears to be partly due to the released glutamate acting at ionotropic receptors on the noradrenergic axons present in the cortical slices. LPS appears to release glutamate, which then acts at non-NMDA receptors to remove the voltage-sensitive Mg2+ block of NMDA receptors, thus permitting NMDA receptors to be activated and noradrenaline release to proceed. It seems possible that rapid, inappropriate excitation may occur in the immediate vicinity of gram-negative bacterial infections in the brain. If similar inappropriate excitations are also triggered by those immunogens specifically associated with Alzheimer's disease (beta-amyloid), AIDS dementia (gp120 and gp41), or multiple sclerosis (myelin basic protein), they might explain some of the acute, transient neurological and psychiatric symptoms associated with these disorders.
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PMID:The bacterial endotoxin lipopolysaccharide causes rapid inappropriate excitation in rat cortex. 993 Jul 37

Multiple sclerosis (MS) is a central nervous disease thought to be elicited by an autoimmune process. Many studies in recent years have concentrated on finding the alterations in the peripheral blood immune profile in MS patients that would reflect disease activity. In the present study, we investigated surface antigen expression on lymphocytes and granulocytes from MS patients and control subjects. We have studied 29 patients suffering from relapsing-remitting or relapsing-progressive forms of MS. The disease was diagnosed in all patients at least 12 months before inclusion into the study. All patients had no attack at the study entry date or within a previous month. The control group included 29 age-matched subjects. Phenotyping of peripheral blood leukocytes was carried out with different fluorescence-conjugated murine monoclonal antibodies. The analysis was performed with three-color flow cytometry. The following antigens were determined [cluster of definition (CD)]: leukocyte common antigen (LCA) (B220, T 200, Ly-5), CD45; LPS-R (lipopolysaccharide receptor), CD14; found on all T cells, CD3; LFA-2 (lymphocyte function associated antigen, T 11), CD2; coreceptor for MHC class II molecules, found on helper T cells, CD4; coreceptor for MHC class I molecules, found on suppressor/cytotoxic T cells, CD8; B4, found on all human B cells, CD19; NCAM (neural cell adhesion molecule), CD56; integrin beta2 subunit, associated with CD11a (CD11a/CD18, LFA-1, alphaLbeta2) and CD11b (CD11b/CD18, Mac-1,CR3, alphaMbeta2), CD18; alphaL, alpha subunit of integrin LFA-1 (alphaLbeta2, CD11a/CD18), CD11a; alphaM, alpha subunit of integrin Mac-1 (CR3, alphaMbeta2, CD11b/CD18), CD11b; ICAM-1 (intercellular adhesion molecule), CD54; H-CAM, Hermes antigen, Pgp-1, CD44; AIM (activation inducer molecule), early activation antigen, CD69; T-cell receptor gammadelta, TCR gammadelta. In the MS group, we have found a significant increased expression of CD54 and CD44 antigens on lymphocytes, and higher percentage CD54(+) and CD11a+CD54(+) lymphocytes out of all lymphocytes compared with the control group. We have also found a significant increased expression of CD11a, CD18 and CD54 antigens on granulocytes, and higher percentage CD11b+CD18(+) granulocytes out of all granulocytes in MS patients compared with control. Higher levels of expression of the adhesion molecules may reflect the activation state of leukocytes in MS patients.
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PMID:Phenotyping analysis of peripheral blood leukocytes in patients with multiple sclerosis. 1021 Sep 17

Type III and IV phosphodiesterase inhibitors (PDEIs) have recently been shown to suppress the production of TNF-alpha in several types of cells. In the present study, we have shown that all the types of PDEIs, from type I- to V-specific and non-specific, suppress the production of TNF-alpha by mouse microglia stimulated with lipopolysaccharide (LPS) in a dose-dependent manner. Certain combinations of three different types of PDEIs synergistically suppressed TNF-alpha production by microglia at a very low concentration (1 microM). Since some PDEIs reportedly pass through the blood-brain barrier (BBB), the combination of three PDEIs may be worth trying in neurological diseases, such as multiple sclerosis and HIV-related neurological diseases in which TNF-alpha may play a critical role. Some PDEIs also suppressed interleukin-I (IL-I) and IL-6 production by mouse microglia stimulated with LPS. In contrast, the production of IL-10, which is known to be an inhibitory cytokine, was upregulated by certain PDEIs. The suppression of TNF-alpha and induction of IL-10 were confirmed at the mRNA level by RT-PCR. PDEIs may be useful anti-inflammatory agents by downregulating inflammatory cytokines and upregulating inhibitory cytokines in the central nervous system. (CNS).
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PMID:Effects of phosphodiesterase inhibitors on cytokine production by microglia. 1033 22

Vesnarinone (OPC-8212) is a synthetic quinolinone derivative with inotropic and immunomodulatory effects. Vesnarinone has been shown to inhibit tumor necrosis factor-alpha (TNF alpha) produced by mitogen stimulated macrophages, and to inhibit phosphodiesterase (PDE) type III in cardiac muscle. TNF alpha and interferon-gamma (IFNgamma) have been implicated in the pathogenesis of autoimmune diseases, and both cytokines are targets for therapeutic intervention. IFNgamma can enhance autoimmune disease through direct effects, and indirectly by priming macrophages to produce TNF alpha. In this study, we demonstrate that while vesnarinone enhances basal TNF alpha levels, it inhibits TNF alpha production in peripheral blood mononuclear cells from multiple sclerosis (MS) patients and healthy donors stimulated with lipopolysaccharide (LPS) or primed with IFNgamma and stimulated with suboptimal doses of LPS. In addition, vesnarinone inhibited TNF alpha production in primary adult human microglial cultures. However, in contrast to rolipram, another TNF alpha inhibiting agent, vesnarinone failed to inhibit TNF alpha production by myelin basic protein specific T-cell lines. As oral TNF inhibitors are currently being considered in the USA for clinical application in MS, the implications of our findings on the development of vesnarinone for treatment of MS are discussed.
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PMID:The effect of vesnarinone on TNF alpha production in human peripheral blood mononuclear cells and microglia: a preclinical study for the treatment of multiple sclerosis. 1040 67

The mechanisms by which IFNbeta-1b acts in the treatment of multiple sclerosis (MS) patients are not completely known. We investigated the influence of IFNbeta-1b on the mRNA-expression of the immunosuppressive cytokine TGFbeta-1 and the proinflammatory mediator TNFalpha in an in vitro model by the method of non-radioactive in situ hybridization. Peripheral blood lymphocytes (PBL) were isolated from eight patients with relapsing remitting form of MS during remission and from six healthy controls. They were stimulated with IFNbeta-1b in different concentrations for 24 h. In both groups a statistically significant dose-dependent increase of TGFbeta-1-mRNA and decrease of TNFalpha-mRNA was demonstrable in the cultured stimulated blood lymphocytes compared to unstimulated cells. Stimulations with lipopolysaccharide (LPS) led to an increase of both cytokine-mRNAs in the lymphocytes. These data suggest specific and dose-dependent effects of IFNbeta-1b and hint at immunomodulatory properties of this drug to regulate the cytokine dysbalance in MS. This might be one mechanism by which IFNbeta-1b mediates its beneficial effects on the course of the disease.
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PMID:Immunomodulatory effects of IFNbeta-1b on the mRNA-expression of TGFbeta-1 and TNFalpha in vitro. 1043 55

Tumor necrosis factor (TNF) alpha, interleukins (IL) 2, 4, 6, and 10, and IgG oligoclonal bands (IgG OB) in vitro production was assessed, after whole-blood stimulation with lipopolysaccharide or concanavalin A, in 61 patients presenting with relapsing-remitting, relapsing-progressive, or chronic progressive multiple sclerosis. Multiple sclerosis patients were receiving no treatment or azathioprine (AZA), cyclosporin, cyclophosphamide, subcutaneous interferon (IFN) beta 1 a, or corticosteroids (CST). Statistical correlations significantly showed that: (a) AZA lowers TNF-alpha (P = 0.002) and increases IL-4 production (P = 0.0024), and IFN-beta 1 a increases TNF-alpha and decreases IL-4 levels; (b) CST has a negative effect on TNF-alpha, IL-6, and IL-4 synthesis; and (c) AZA, IFN-beta 1 a, and CST diminish IgG OB synthesis (P = 0.001). Although our study of the dynamics of TNF-alpha, IL-2, IL-4, IL-6, and IL-10 in vitro production generally found no statistically significant correlations (partly explained by the limited number of values in the various groups), IL-6 was shown to drop during the periods surrounding relapse (P = 0.05) in the absence of treatment, while TNF-alpha (P = 0.04) and IL-6 (P < 0.05) dropped before exacerbation in the presence of AZA. In vitro production of TNF-alpha was closely and positively correlated with that of IL-6, independently of clinical features. The enhanced production of IL-10 detected before or at relapse with AZA and IFN-beta 1 a (trends) may interfere with initiation of the immune reaction and with the development of new CNS lesions. Some discrepancies with previously published results stress the difficulties in studying the state of stimulation of different populations of leukocytes by using a variety of in vitro stimuli and in establishing a correlation between mRNA studies and the amount of final or active protein produced.
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PMID:Assessing multiple sclerosis activity: is the in vitro production of tumor necrosis factor-alpha, interleukins 2, 6, 4, and 10, and immunoglobulin G of value? 1063 36

Type I interferons (IFN) are widely used for the therapeutic treatment of viral infections, tumor growth and various chronic diseases such as multiple sclerosis. Antagonism between type I IFNs and IFN-gamma has been described in cells of the immune system, in particular in the activation of macrophages. To study the systemic effects of type I IFNs we used transgenic mice carrying a human IFN-beta (hIFN-beta) gene under the control of the rat insulin I promoter. These animals expressed high levels of hIFN-beta in beta-pancreatic cells, and the ability of the macrophages to respond to pro-inflammatory stimuli was analyzed. Transgenic mice exhibited an increased extravasation of cells to the peritoneal cavity after eliciting with thioglycollate broth. The expression of the inducible form of nitric oxide synthase and cyclooxygenase-2, two enzymes involved in inflammation, was impaired in transgenic animals challenged with lipopolysaccharide and IFN-gamma. Analysis of the mechanisms leading to this attenuated inflammatory response showed a decrease in the serum levels of TNF-alpha and an inhibition of the activation of the transcription factor NF-KB in various tissues. These results indicate that systemic administration of IFN-beta might influence the response to pro-inflammatory stimuli, in particular through the antagonism of IFN-gamma signaling.
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PMID:Anti-inflammatory action of type I interferons deduced from mice expressing interferon beta. 1084 18

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