scholarly journals Stimulation of tumor necrosis factor alpha production in human monocytes by inhibitors of protein phosphatase 1 and 2A.

1992 ◽  
Vol 176 (3) ◽  
pp. 897-901 ◽  
Author(s):  
S J Sung ◽  
J A Walters ◽  
S M Fu
Keyword(s):  
Okadaic Acid ◽  
Mrna Stability ◽  
Protein Phosphatase ◽  
Protein Phosphatase 1 ◽  
Tnf Alpha ◽  
Mrna Accumulation ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Stimulation Of

The protein phosphatase 1 and 2A inhibitor, okadaic acid, has been shown to stimulate many cellular functions by increasing the phosphorylation state of phosphoproteins. In human monocytes, okadaic acid by itself stimulates tumor necrosis factor alpha (TNF-alpha) mRNA accumulation and TNF-alpha synthesis. Calyculin A, a more potent inhibitor of phosphatase 1, has similar effects. TNF-alpha mRNA accumulation in okadaic acid-treated monocytes is due to increased TNF-alpha mRNA stability and transcription rate. The increase in TNF-alpha mRNA stability is more remarkable in okadaic acid-treated monocytes than the mRNA stability of other cytokines, such as interleukin 1 alpha (IL-1 alpha), IL-1 beta, and IL-6. Gel retardation studies show the stimulation of AP-1, AP-2, and NF-kappa B binding activities in okadaic acid-stimulated monocytes. This increase may correlate with the increase in TNF-alpha mRNA transcription rate. In addition to the stimulation of TNF-alpha secretion by monocytes, okadaic acid appears to modulate TNF-alpha precursor processing, as indicated by a marked increase in the cell-associated 26-kD precursor. These results suggest that active basal phosphorylation/dephosphorylation occurs in monocytes, and that protein phosphatase 1 or 2A is important in regulating TNF-alpha gene transcription, translation, and posttranslational modification.

scholarly journals Bifunctional effects of tumor necrosis factor alpha (TNF alpha) on the growth of mature and primitive human hematopoietic progenitor cells: involvement of p55 and p75 TNF receptors

Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3152-3159 ◽  
Author(s):  
LS Rusten ◽  
FW Jacobsen ◽  
W Lesslauer ◽  
H Loetscher ◽  
EB Smeland ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Colony Growth ◽  
Tnf Alpha ◽  
Tnf Receptors ◽  
Hematopoietic Progenitor ◽  
Necrosis Factor Alpha ◽  
Gm Csf ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Stimulation Of

Abstract Tumor necrosis factor alpha (TNF alpha) has previously been reported to have both inhibitory and stimulatory effects on hematopoietic progenitor cells. Specifically, TNF alpha has been proposed to stimulate early hematopoiesis in humans. In the present study we show that TNF alpha, in a dose-dependent fashion, can potently inhibit the growth of primitive high proliferative potential colony-forming cells (HPP-CFCs) stimulated by multiple cytokine combinations. Using agonistic antibodies to the p55 and p75 TNF receptors or TNF alpha mutants specific for either of the two TNF receptors, we show that both receptors can mediate this inhibition. In contrast, the potent stimulation of interleukin-3 (IL-3) plus granulocyte-macrophage colony- stimulating factor (GM-CSF) induced HPP-CFC colony formation observed at low concentrations of TNF alpha (2 ng/mL) was only a p55-mediated event. Moreover, the stimulatory effects of TNF alpha on GM-CSF or IL-3- induced colony formation, as well as the inhibition of G-CSF-induced colony growth, were also exclusively signaled through the p55 TNF receptor. Taken together, our results suggest that the inhibitory effects of TNF alpha on primitive bone marrow progenitor cells are mediated through both p55 and p75 TNF receptors, whereas the p55 receptor exclusively mediates the bidirectional effects on more mature, single factor-responsive bone marrow progenitor cells as well as stimulation of IL-3 plus GM-CSF-induced HPP-CFC colony growth.

scholarly journals Release of both preformed and newly synthesized tumor necrosis factor alpha (TNF-alpha)/cachectin by mouse mast cells stimulated via the Fc epsilon RI. A mechanism for the sustained action of mast cell-derived TNF-alpha during IgE-dependent biological responses.

1991 ◽  
Vol 174 (1) ◽  
pp. 103-107 ◽  
Author(s):  
J R Gordon ◽  
S J Galli
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Tumor Necrosis Factor ◽  
Sustained Release ◽  
Tumor Necrosis ◽  
Tnf Alpha ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Stimulation Of

Mast cell-associated mediators are generally classified into two groups: the preformed mediators, which are stored in the cells' cytoplasmic granules and are released upon exocytosis, and the newly synthesized mediators, which are not stored but are produced and secreted only after appropriate stimulation of the cell. We now report that tumor necrosis factor alpha (TNF-alpha)/cachectin represents a new type of mast cell-associated mediator, in that IgE-dependent mast cell activation results in the rapid release of preformed stores of the cytokine followed by the synthesis and sustained release of large quantities of newly formed TNF-alpha. We also demonstrate that challenge with specific antigen induces higher levels of TNF-alpha mRNA at skin sites sensitized with IgE in normal mice or mast cell-reconstituted genetically mast cell-deficient WBB6F1-W/W1' mice than at identically treated sites in WBB6F1-W/W1' mice that are devoid of mast cells. These findings identify mast cells as a biologically significant source of TNF-alpha/cachectin during IgE-dependent responses and define a mechanism whereby stimulation of mast cells via the FC epsilon RI can account for both the rapid and sustained release of this cytokine.

scholarly journals Recombinant human tumor necrosis factor alpha regulates c-myc expression in HL-60 cells at the level of transcription

Blood ◽  
1987 ◽  
Vol 70 (1) ◽  
pp. 200-205
Author(s):  
A Tobler ◽  
D Johnston ◽  
HP Koeffler
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Human Tumor ◽  
Tnf Alpha ◽  
Mrna Levels ◽  
Human Tumor Necrosis Factor ◽  
Mrna Accumulation ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor

Recombinant human tumor necrosis factor alpha (TNF alpha) effectively inhibits clonal growth of leukemic cells from patients and several cell lines, including the promyelocytic HL-60 cells. Decreased expression of the c-myc oncogene is linked to growth arrest and terminal cellular differentiation. The present study characterizes the effect of TNF alpha on the regulation of the c-myc gene in HL-60 cells. TNF alpha (100 U/mL) rapidly inhibited messenger RNA (mRNA) accumulation of c-myc with a 50% reduction in less than one hour. Dose-response studies showed that a 50% reduction of c-myc mRNA occurred in the range of 15 U/mL. In vitro nuclear run-on experiments showed that this decrease of c-myc-mRNA accumulation was the result of a reduced rate of transcription of c-myc by TNF alpha. Further studies demonstrated that TNF alpha did not post-transcriptionally alter levels of c-myc mRNA, and the inhibitory action of TNF alpha on c-myc expression in HL-60 cells did not depend on new protein synthesis. In the conditions of all the experiments, TNF alpha did not affect cell viability. By contrast, TNF alpha (500 U/mL) did not decrease mRNA levels of c-myc in an HL-60 variant cell line whose growth was not inhibited by TNF alpha; also TNF alpha (500 U/mL) increased c-myc-mRNA levels in normal fibroblasts whose growth is known to be stimulated by TNF alpha. These findings, in concert with prior studies, show a close association between growth inhibition of HL-60 cells and decreased levels of mRNA coding for c-myc.

scholarly journals Bifunctional effects of tumor necrosis factor alpha (TNF alpha) on the growth of mature and primitive human hematopoietic progenitor cells: involvement of p55 and p75 TNF receptors

Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3152-3159 ◽  
Author(s):  
LS Rusten ◽  
FW Jacobsen ◽  
W Lesslauer ◽  
H Loetscher ◽  
EB Smeland ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Colony Growth ◽  
Tnf Alpha ◽  
Tnf Receptors ◽  
Hematopoietic Progenitor ◽  
Necrosis Factor Alpha ◽  
Gm Csf ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Stimulation Of

Tumor necrosis factor alpha (TNF alpha) has previously been reported to have both inhibitory and stimulatory effects on hematopoietic progenitor cells. Specifically, TNF alpha has been proposed to stimulate early hematopoiesis in humans. In the present study we show that TNF alpha, in a dose-dependent fashion, can potently inhibit the growth of primitive high proliferative potential colony-forming cells (HPP-CFCs) stimulated by multiple cytokine combinations. Using agonistic antibodies to the p55 and p75 TNF receptors or TNF alpha mutants specific for either of the two TNF receptors, we show that both receptors can mediate this inhibition. In contrast, the potent stimulation of interleukin-3 (IL-3) plus granulocyte-macrophage colony- stimulating factor (GM-CSF) induced HPP-CFC colony formation observed at low concentrations of TNF alpha (2 ng/mL) was only a p55-mediated event. Moreover, the stimulatory effects of TNF alpha on GM-CSF or IL-3- induced colony formation, as well as the inhibition of G-CSF-induced colony growth, were also exclusively signaled through the p55 TNF receptor. Taken together, our results suggest that the inhibitory effects of TNF alpha on primitive bone marrow progenitor cells are mediated through both p55 and p75 TNF receptors, whereas the p55 receptor exclusively mediates the bidirectional effects on more mature, single factor-responsive bone marrow progenitor cells as well as stimulation of IL-3 plus GM-CSF-induced HPP-CFC colony growth.

scholarly journals Regulation of tumor necrosis factor alpha transcription in macrophages: involvement of four kappa B-like motifs and of constitutive and inducible forms of NF-kappa B.

1990 ◽  
Vol 10 (4) ◽  
pp. 1498-1506 ◽  
Author(s):  
M A Collart ◽  
P Baeuerle ◽  
P Vassalli
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Tnf Alpha ◽  
Nf Kappa B ◽  
Necrosis Factor Alpha ◽  
Protein Subunits ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Stimulation Of

This study characterizes the interaction of murine macrophage nuclear proteins with the tumor necrosis factor alpha (TNF-alpha) promoter. Gel retardation and methylation interference assays showed that stimulation of TNF-alpha gene transcription in peritoneal exudate macrophages was accompanied by induction of DNA-binding proteins that recognized with different affinities four elements related to the kappa B consensus motif and a Y-box motif. We suggest that the basal level of TNF-alpha expression in macrophages is due to the binding of a constitutive form of NF-kappa B, present at low levels in nuclei from resting thioglycolate exudate peritoneal macrophages, to some if not all of the kappa B motifs; we postulate that this constitutive form contains only the 50-kilodalton (kDa) DNA-binding protein subunits of NF-kappa B, not the 65-kDa protein subunits (P. Baeuerle and D. Baltimore, Genes Dev. 3:1689-1698, 1989). Agents such as glucocorticoids, which decrease TNF-alpha transcription, diminished the basal level of nuclear NF-kappa B. Stimulation of Stimulation of TNF-alpha transcription in macrophages by lipopolysaccharide, gamma interferon, or cycloheximide led to an increased content of nuclear NF-kappa B. This induced factor represents a different form of NF-kappa B, since it generated protein-DNA complexes of slower mobility; we propose that this induced form of NF-kappa B contains both the 50- and 65-kDa protein subunits, the latter ones being necessary to bind NF-kappa B to its cytoplasmic inhibitor in uninduced cells (Baeuerle and Baltimore, Genes Dev., 1989). In resting cells, this inducible form of NF-kappa B was indeed detectable in the cytosol after deoxycholate treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Regulation of tumour necrosis factor-alpha release from human adipose tissue in vitro

1999 ◽  
Vol 163 (1) ◽  
pp. 33-38 ◽  
Author(s):  
CP Sewter ◽  
JE Digby ◽  
F Blows ◽  
J Prins ◽  
S O'Rahilly
Keyword(s):  
Adipose Tissue ◽  
Human Adipose Tissue ◽  
Tumour Necrosis Factor Alpha ◽  
Host Defence ◽  
Tnf Alpha ◽  
Necrosis Factor Alpha ◽  
Isolated Adipocytes ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Stimulation Of

Tumour necrosis factor-alpha (TNF-alpha), secreted by cells of the macrophage-monocyte lineage, has a well established role in inflammation and host-defence. The more recent discovery that adipocytes also secrete TNF-alpha has led to a substantial body of research implicating this molecule in the insulin resistance of obesity. However, little is known about the normal regulation of TNF-alpha release from human adipose tissue. In particular, it is not known whether adipocyte production of TNF-alpha is responsive to similar or different molecular regulators than those relevant to macrophages. TNF-alpha release from cultured human adipose tissue and isolated adipocytes was examined using an ELISA. Insulin, cortisol or the thiazolidinedione, BRL 49653, did not have a significant effect on TNF-alpha release from adipose tissue or isolated adipocytes. In contrast, lipopolysaccharide (LPS), a major stimulus of TNF-alpha protein production in monocytes and macrophages, resulted in a fivefold stimulation of TNF-alpha release from human adipose tissue. Significant stimulation of TNF-alpha release was also seen from isolated adipocytes, indicating that the increase in TNF-alpha release from adipose tissue in the presence of LPS is unlikely to be entirely attributable to contaminating monocytes or macrophages. Consistent with this observation was the finding that mRNA for CD14, a known cellular receptor for LPS, is expressed in human adipocytes. The increase in TNF-alpha protein release in response to LPS was blocked by an inhibitor of the matrix metalloproteinase responsible for the cleavage of the membrane-bound proform of TNF-alpha, indicating that this release represented regulated secretion and was not due to cell lysis. In conclusion, the regulation of TNF-alpha protein release from human adipose tissue and isolated adipocytes appears to be similar to its regulation in cell types more traditionally implicated in host defence. The production by the adipocyte of a range of molecules involved in host defence-TNF-alpha, factors D, B and C3, interleukin-6, and macrophage colony-stimulating factor--suggest that this cell type may make a significant contribution to innate immunity.

scholarly journals Differential regulation of human B-lymphocyte tumor necrosis factor- alpha (TNF-alpha) and lymphotoxin (TNF-beta) production by protein phosphatase 1 and 2A inhibitor

Blood ◽  
1993 ◽  
Vol 82 (9) ◽  
pp. 2806-2812
Author(s):  
HZ Xia ◽  
CC Kannapell ◽  
SM Fu ◽  
SS Sung
Keyword(s):  
Tumor Necrosis Factor ◽  
Gene Transcription ◽  
Okadaic Acid ◽  
Tumor Necrosis ◽  
B Lymphocyte ◽  
Cytokine Production ◽  
Tnf Alpha ◽  
Mrna Accumulation ◽  
Necrosis Factor Alpha ◽  
Necrosis Factor

Tumor necrosis factor (TNF) and lymphotoxin (LT; TNF-beta) are major cytokines produced by B lymphocytes. Stimulation by okadaic acid, a phosphatase 1 and 2A inhibitor, markedly increased TNF mRNA accumulation and cytokine production. On the other hand, the accumulation of LT mRNA was not affected by okadaic acid despite structural and functional similarities between TNF and LT. The increase in TNF mRNA accumulation was due to the stimulation of gene transcription and a marked stabilization of this mRNA. The binding activities of the transcription factors AP-1 and AP-2 and NF kappa B, which regulates TNF gene transcription, were also stimulated by okadaic acid. In addition, okadaic acid was shown to increase TNF production at the protein level. These results show the importance of protein phosphatases in the regulation of cytokine production in B cells, and further identifies differences in the regulation of TNF-alpha and LT production.

Differential regulation of human B-lymphocyte tumor necrosis factor- alpha (TNF-alpha) and lymphotoxin (TNF-beta) production by protein phosphatase 1 and 2A inhibitor

Blood ◽  
1993 ◽  
Vol 82 (9) ◽  
pp. 2806-2812 ◽  
Author(s):  
HZ Xia ◽  
CC Kannapell ◽  
SM Fu ◽  
SS Sung
Keyword(s):  
Tumor Necrosis Factor ◽  
Gene Transcription ◽  
Okadaic Acid ◽  
Tumor Necrosis ◽  
B Lymphocyte ◽  
Cytokine Production ◽  
Tnf Alpha ◽  
Mrna Accumulation ◽  
Necrosis Factor Alpha ◽  
Necrosis Factor

Abstract Tumor necrosis factor (TNF) and lymphotoxin (LT; TNF-beta) are major cytokines produced by B lymphocytes. Stimulation by okadaic acid, a phosphatase 1 and 2A inhibitor, markedly increased TNF mRNA accumulation and cytokine production. On the other hand, the accumulation of LT mRNA was not affected by okadaic acid despite structural and functional similarities between TNF and LT. The increase in TNF mRNA accumulation was due to the stimulation of gene transcription and a marked stabilization of this mRNA. The binding activities of the transcription factors AP-1 and AP-2 and NF kappa B, which regulates TNF gene transcription, were also stimulated by okadaic acid. In addition, okadaic acid was shown to increase TNF production at the protein level. These results show the importance of protein phosphatases in the regulation of cytokine production in B cells, and further identifies differences in the regulation of TNF-alpha and LT production.

scholarly journals Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) is required for lipopolysaccharide stimulation of tumor necrosis factor alpha (TNF-alpha) translation: glucocorticoids inhibit TNF-alpha translation by blocking JNK/SAPK.

1997 ◽  
Vol 17 (11) ◽  
pp. 6274-6282 ◽  
Author(s):  
J L Swantek ◽  
M H Cobb ◽  
T D Geppert
Keyword(s):  
Protein Kinase ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Family Members ◽  
Tnf Alpha ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Stimulation Of

The adverse effects of lipopolysaccharide (LPS) are mediated primarily by tumor necrosis factor alpha (TNF-alpha). TNF-alpha production by LPS-stimulated macrophages is regulated at the levels of both transcription and translation. It has previously been shown that several mitogen-activated protein kinases (MAPKs) are activated in response to LPS. We set out to determine which MAPK signaling pathways are activated in our system and which MAPK pathways are required for TNF-alpha gene transcription or TNF-alpha mRNA translation. We confirm activation of the MAPK family members extracellular-signal-regulated kinases 1 and 2 (ERK1 and ERK2), p38, and Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK), as well as activation of the immediate upstream MAPK activators MAPK/ERK kinases 1 and 4 (MEK1 and MEK4). We demonstrate that LPS also activates MEK2, MEK3, and MEK6. Furthermore, we demonstrate that dexamethasone, which inhibits the production of cytokines, including TNF-alpha, significantly inhibits LPS induction of JNK/SAPK activity but not that of p38, ERK1 and ERK2, or MEK3, MEK4, or MEK6. Dexamethasone also blocks the sorbitol but not anisomycin stimulation of JNK/SAPK activity. A kinase-defective mutant of SAPKbeta, SAPKbeta K-A, blocked translation of TNF-alpha, as determined by using a TNF-alpha translational reporting system. Finally, overexpression of wild-type SAPKbeta was able to overcome the dexamethasone-induced block of TNF-alpha translation. These data confirm that three MAPK family members and their upstream activators are stimulated by LPS and demonstrate that JNK/SAPK is required for LPS-induced translation of TNF-alpha mRNA. A novel mechanism by which dexamethasone inhibits translation of TNF-alpha is also revealed.

scholarly journals Stimulation of fibroblast chemotaxis by human recombinant tumor necrosis factor alpha (TNF-alpha) and a synthetic TNF-alpha 31-68 peptide.

1990 ◽  
Vol 172 (6) ◽  
pp. 1749-1756 ◽  
Author(s):  
A E Postlethwaite ◽  
J M Seyer
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Tnf Alpha ◽  
Necrosis Factor Alpha ◽  
Fibroblast Migration ◽  
Factor Alpha ◽  
Recombinant Tumor Necrosis Factor ◽  
Necrosis Factor ◽  
Stimulation Of

Macrophages are a major source of fibrogenic factors that promote healing of injured tissue. The recruitment of fibroblasts to sites of tissue injury is a prerequisite for optimal repair of tissue damage. In the present study, human recombinant tumor necrosis factor alpha (hrTNF-alpha), a major macrophage-derived cytokine, was demonstrated to be a potent fibroblast chemoattractant, inducing migration at picomolar concentrations. Anti-hrTNF-alpha monoclonal antibody neutralized most of the fibroblast chemotactic activity generated during short-term culture of human peripheral blood monocytes stimulated with bacterial lipopolysaccharide, suggesting that TNF-alpha is a major monocyte-derived fibroblast chemoattractant. The portion of the human TNF-alpha molecule responsible for its chemotactic stimulation of fibroblasts appears to reside in residues 31-68. This region is highly conserved between TNF-alpha and lymphotoxin. This peptide is not only itself chemotactic but is also able to block the chemotactic response of fibroblasts to hrTNF-alpha and vice versa, suggesting that they each mediate fibroblast migration through similar mechanisms. These data further underscore the potential importance of TNF-alpha in modulating a variety of fibroblast functions, including chemotaxis and synthesis of collagen, glycosaminoglycans, interleukin 1 alpha (IL-1 alpha) and -beta, human histocompatibility leukocyte antigen A and B antigens, collagenase, prostaglandin E2, and IL-6.

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