scholarly journals Differential tumor necrosis factor alpha expression by astrocytes from experimental allergic encephalomyelitis-susceptible and -resistant rat strains.

1991 ◽  
Vol 173 (4) ◽  
pp. 801-811 ◽  
Author(s):  
I Y Chung ◽  
J G Norris ◽  
E N Benveniste
Keyword(s):  
Gene Expression ◽  
Tnf Alpha ◽  
Allergic Encephalomyelitis ◽  
Necrosis Factor Alpha ◽  
Ifn Gamma ◽  
Alpha Production ◽  
Factor Alpha ◽  
Alpha Gene ◽  
Necrosis Factor ◽  
Experimental Allergic

There is evidence that the cytokine tumor necrosis factor alpha (TNF-alpha) contributes to the pathogenesis of neurological autoimmune diseases such as multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE). TNF-alpha exerts damaging effects on oligodendrocytes, the myelin-producing cell of the central nervous system (CNS), and myelin itself. We have recently demonstrated TNF-alpha expression from astrocytes induced by lipopolysaccharide (LPS), interferon gamma (IFN-gamma), and interleukin 1 beta (IL-1 beta). Astrocytes secrete TNF-alpha in response to LPS alone, and can be primed by IFN-gamma to enhance LPS-induced TNF-alpha production. IFN-gamma and IL-1 beta, cytokines known to be present in the CNS during neurological disease states, do not induce TNF-alpha production alone, but act synergistically to stimulate astrocyte TNF-alpha expression. Inbred Lewis and Brown-Norway (BN) rats differ in genetic susceptibility to EAE, which is controlled in part by major histocompatibility complex (MHC) genes. We examined TNF-alpha gene expression by astrocytes derived from BN rats (resistant to EAE) and Lewis rats (highly susceptible). Astrocytes from BN rats express TNF-alpha mRNA and protein in response to LPS alone, yet IFN-gamma does not significantly enhance LPS-induced TNF-alpha expression, nor do they express appreciable TNF-alpha in response to the combined stimuli of IFN-gamma/IL-1 beta. In contrast, astrocytes from Lewis rats express low levels of TNF-alpha mRNA and protein in response to LPS, and are extremely responsive to the priming effect of IFN-gamma for subsequent TNF-alpha gene expression. Also, Lewis astrocytes produce TNF-alpha in response to IFN-gamma/IL-1 beta. The differential TNF-alpha production by astrocytes from BN and Lewis strains is not due to the suppressive effect of prostaglandins, because the addition of indomethacin does not alter the differential pattern of TNF-alpha expression. Furthermore, Lewis and BN astrocytes produce another cytokine, IL-6, in response to LPS, IFN-gamma, and IL-1 beta in a comparable fashion. Peritoneal macrophages and neonatal microglia from Lewis and BN rats are responsive to both LPS and IFN-gamma priming signals for subsequent TNF-alpha production, suggesting that differential TNF-alpha expression by the astrocyte is cell type specific. Taken together, these results suggest that differential TNF-alpha gene expression in response to LPS and IFN-gamma is strain and cell specific, and reflects both transcriptional and post-transcriptional control mechanisms.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Polymorphisms in the tumor necrosis factor alpha (TNF-alpha) gene correlate with murine resistance to development of toxoplasmic encephalitis and with levels of TNF-alpha mRNA in infected brain tissue.

1992 ◽  
Vol 175 (3) ◽  
pp. 683-688 ◽  
Author(s):  
Y R Freund ◽  
G Sgarlato ◽  
C O Jacob ◽  
Y Suzuki ◽  
J S Remington
Keyword(s):  
Brain Tissue ◽  
Tumor Necrosis ◽  
Toxoplasmic Encephalitis ◽  
Tnf Alpha ◽  
Necrosis Factor Alpha ◽  
Alpha Production ◽  
D Region ◽  
Factor Alpha ◽  
Alpha Gene ◽  
Necrosis Factor

Murine resistance to development of toxoplasmic encephalitis (TE) has recently been mapped to the D region of the major histocompatibility complex (H-2). Since the gene for tumor necrosis factor alpha (TNF-alpha) is located 5' of the D region and TNF-alpha has been implicated as playing a role in neurological diseases, we were interested in determining the relationship of TNF-alpha production to TE resistance. We have demonstrated that resistance to TE in inbred mice can be correlated with specific restriction fragment length polymorphisms and microsatellite variants in the TNF-alpha gene. Mice that are susceptible to TE express elevated levels of TNF-alpha mRNA in brain tissue 6 wk after infection with the ME49 strain of Toxoplasma gondii. Resistant mice and all mice that are uninfected show no detectable TNF-alpha mRNA expression in brain tissue. Differences in the TNF-alpha gene between susceptible and resistant mice have been localized to the first intron, the promoter, and the 3' end of the TNF-alpha gene. These data implicate differences in regulation of TNF-alpha production in brain tissue as contributing to differences in susceptibility to development of TE.

scholarly journals Regulation of cytokine production by soluble CD23: costimulation of interferon gamma secretion and triggering of tumor necrosis factor alpha release.

1994 ◽  
Vol 180 (3) ◽  
pp. 1005-1011 ◽  
Author(s):  
M Armant ◽  
H Ishihara ◽  
M Rubio ◽  
G Delespesse ◽  
M Sarfati
Keyword(s):  
Tumor Necrosis Factor ◽  
Interferon Gamma ◽  
Tumor Necrosis ◽  
Cytokine Production ◽  
Tnf Alpha ◽  
Necrosis Factor Alpha ◽  
Ifn Gamma ◽  
Alpha Production ◽  
Factor Alpha ◽  
Necrosis Factor

Soluble CD23 (sCD23) has multiple IgE-independent biological activities. In the present study, we examined the regulatory effect of sCD23 on cytokine production by human peripheral blood mononuclear cells (PBMC). We show that sCD23 enhances by about 80-fold the interleukin 2 (IL-2)-induced interferon gamma (IFN-gamma) production and by about 10-fold the response to IL-12. This potentiating activity is time and dose dependent and is not associated with a significant effect on DNA synthesis. The sCD23 costimulatory activity for IFN-gamma synthesis is drastically reduced in monocyte-depleted PBMC, suggesting that monocytes may be the target for sCD23. This hypothesis was supported by the following observations. First, sCD23 alone is a potent inducer of tumor necrosis factor alpha (TNF-alpha) production by PBMC and this effect disappears after monocyte depletion. The triggering of TNF-alpha release is specifically inhibited by neutralizing anti-CD23 monoclonal antibody (mAb). In addition, IL-2 and IL-12 synergize with sCD23 to induce TNF-alpha production. Second, sCD23 triggers the release of other inflammatory mediators such as IL-1 alpha, IL-1 beta, and IL-6. Finally, TNF-alpha production in response to IL-2 and sCD23 precedes IFN-gamma and IFN-gamma secretion is significantly inhibited by anti-TNF-alpha mAb, indicating that the sCD23 costimulatory signal for IFN-gamma production may be partially mediated by TNF-alpha release. It is proposed that sCD23 is a proinflammatory cytokine that, in addition, may play an important role in the control of the immune response via the enhancement of IFN-gamma production.

scholarly journals Synergistic activation of NF-kappaB by tumor necrosis factor alpha and gamma interferon via enhanced I kappaB alpha degradation and de novo I kappaBbeta degradation.

1997 ◽  
Vol 17 (11) ◽  
pp. 6746-6754 ◽  
Author(s):  
J L Cheshire ◽  
A S Baldwin
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Tumor Necrosis ◽  
Tnf Alpha ◽  
Necrosis Factor Alpha ◽  
Ifn Gamma ◽  
Effective Immune Response ◽  
Factor Alpha ◽  
Nf Kappab ◽  
Necrosis Factor

Tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma) are required for an effective immune response to bacterial infection and these cytokines synergize in a variety of biological responses, including the induction of cytokine, cell adhesion, and inducible nitrous oxide synthase gene expression. Typically, the synergistic effect on gene expression is due to the independent activation of nuclear factor kappaB (NF-kappaB) by TNF-alpha and of signal transducers and activators of transcription or IFN-regulatory factor 1 by IFNs, allowing these transcription factors to bind their unique promoter sites. However, since activation of NF-kappaB by TNF-alpha is often transient and would not activate long-term kappaB-dependent transcription effectively, we explored the effects of IFN-gamma on TNF-alpha-induced NF-kappaB activity. IFN-gamma, which typically does not activate NF-kappaB, synergistically enhanced TNF-alpha-induced NF-kappaB nuclear translocation via a mechanism that involves the induced degradation of I kappaBbeta and that apparently requires tyrosine kinase activity in preneuronal cells but not in endothelial cells. Correspondingly, cotreatment of cells with TNF-alpha and IFN-gamma leads to persistent activation of NF-kappaB and to potent activation of kappaB-dependent gene expression, which may explain, at least in part, the synergy observed between these cytokines, as well as their involvement in the generation of an effective immune response.

scholarly journals Cross-linking of CD4 molecules upregulates Fas antigen expression in lymphocytes by inducing interferon-gamma and tumor necrosis factor- alpha secretion

Blood ◽  
1994 ◽  
Vol 84 (8) ◽  
pp. 2622-2631 ◽  
Author(s):  
N Oyaizu ◽  
TW McCloskey ◽  
S Than ◽  
R Hu ◽  
VS Kalyanaraman ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Apoptosis ◽  
Tumor Necrosis ◽  
Tnf Alpha ◽  
Cross Linking ◽  
Necrosis Factor Alpha ◽  
Ifn Gamma ◽  
T Cell Apoptosis ◽  
Factor Alpha ◽  
Necrosis Factor

Abstract We have recently shown that, in unfractioned peripheral blood mononuclear cells (PBMCs), the cross-linking of CD4 molecules (CD4XL) is sufficient to induce T-cell apoptosis. However, the underlying mechanism for the CD4XL-mediated T-cell apoptosis is largely unknown. Several recent studies have shown that Fas antigen (Ag), a cell-surface molecule, mediates apoptosis-triggering signals. We show here that cross-linking of CD4 molecules, induced either by anti-CD4 monoclonal antibody (MoAb) Leu3a or by human immunodeficiency virus-1 (HIV-1) envelope protein gp160, upregulates Fas Ag expression as well as Fas mRNA in normal lymphocytes. Addition of the tyrosine protein kinase inhibitor genistein or of the immunosuppressive agent cyclosporin A abrogated these effects. The upregulation of Fas Ag closely correlated with apoptotic cell death, as determined by flow cytometry. In addition, CD4XL resulted in the induction of interferon-gamma (IFN- gamma) and tumor necrosis factor-alpha (TNF-alpha) in the absence of interleukin-2 (IL-2) and IL-4 secretion in PBMCs. Both INF-gamma and TNF-alpha were found to contribute to Fas Ag upregulation and both anti- IFN-gamma and anti-TNF-alpha antibodies blocked CD4XL-induced Fas Ag upregulation and lymphocyte apoptosis. These findings strongly suggest that aberrant cytokine secretion induced by CD4XL and consequent upregulation of Fas Ag expression might play a critical role in triggering peripheral T-cell apoptosis and thereby contribute to HIV disease pathogenesis.

Tumor necrosis factor-alpha and interferon-gamma reduce prolactin release in vitro

1990 ◽  
Vol 259 (5) ◽  
pp. E672-E676
Author(s):  
P. E. Walton ◽  
M. J. Cronin
Keyword(s):  
Anterior Pituitary ◽  
Tumor Necrosis ◽  
Cell Function ◽  
Tnf Alpha ◽  
Pituitary Cells ◽  
Prolactin Release ◽  
Necrosis Factor Alpha ◽  
Ifn Gamma ◽  
Factor Alpha ◽  
Necrosis Factor

Prolactin binds to lymphocytes and monocytes and can modulate immune cell function. It was postulated that proteins released from activated macrophages and lymphocytes could directly influence prolactin release and thus form an endocrine control loop during infection, tumor invasion, or inflammation. This hypothesis was tested by exposing cultured rat anterior pituitary cells to murine tumor necrosis factor-alpha (TNF-alpha) and/or interferon-gamma (IFN-gamma) for 24 h before a 4-h test of cell function. Overall prolactin accumulation during this first 24 h was inhibited by TNF-alpha and markedly reduced by TNF-alpha plus IFN-gamma. In contrast, thyroid-stimulating hormone levels were unchanged in these same media. During the subsequent 4-h challenge, both cytokines reduced thyrotropin-releasing hormone-stimulated prolactin release but had no effect on inhibited prolactin release mediated by dopamine and somatostatin receptors. Cellular viability (assessed by trypan blue and chromium release assays) and prolactin cell content were unchanged after TNF-alpha or IFN-gamma treatment. We conclude that both TNF-alpha and IFN-gamma have the potential to act directly on anterior pituitary cells to slow the rate of prolactin release.

STAT PROTEINS PLAY A ROLE IN TUMOR NECROSIS FACTOR ALPHA GENE EXPRESSION

Shock ◽  
2000 ◽  
Vol 14 (3) ◽  
pp. 400-403 ◽  
Author(s):  
Vicky L. Chappell ◽  
Long X. Le ◽  
Lavenia LaGrone ◽  
William J. Mileski
Keyword(s):  
Gene Expression ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Necrosis Factor Alpha ◽  
Stat Proteins ◽  
Factor Alpha ◽  
Alpha Gene ◽  
Necrosis Factor
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