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S Page

Publications and source records attributed to S Page.

At least 37 records · Page 2Linked to original sources
PubMed1999

Involvement of nuclear factor-kappaB in a murine model for the acute form of autoimmune-like toxic oil syndrome.

The toxic oil syndrome (TOS) represents an exogenously induced autoimmune disease with acute or chronic symptoms similar to systemic lupus erythematosus or scleroderma. When genetically different mouse strains were exposed to oleic acid anilide (OAA), it was possible to mimic the different syndrome manifestations. The aim of the present study was to examine the role of NF-kappaB/Rel transcription factors in the development of the severe acute wasting disease observed in A/J mice. Within a week of OAA exposure, the A/J, but not B10.S strain, displayed weight loss, cachexia, apathy, reduced activity, and breathing difficulties. In affected A/J mice we observed a marked increase in NF-kappaB activation (p50/p65 dimers) both in splenic T cells and peritoneal macrophages as well as in tissue from aorta and gut. Incubation of splenocytes with OAA in vitro induced a dose-dependent removal of IkappaB-alpha, accompanied by NF-kappaB activation, whereas Sp-1 binding was not affected. Furthermore, we demonstrated the increased expression of the two NF-kappaB target genes IL-6 and IL-1beta in OAA-exposed mice and a transient OAA-induced accumulation of TNFalpha in vitro. This is the first report which implicates NF-kappaB/Rel in acute forms of chemically induced autoimmune-like disease and may serve as a paradigm for the involvement of this transcriptional system in acute processes associated with autoimmunity, suggesting possible avenues of therapeutic intervention.

Acute Disease↗
PubMed1999

4-Hydroxynonenal prevents NF-kappaB activation and tumor necrosis factor expression by inhibiting IkappaB phosphorylation and subsequent proteolysis.

Extensively oxidized low density lipoprotein (ox-LDL), a modulator of atherogenesis, down-regulates the lipopolysaccharide (LPS)-induced activation of transcription factor NF-kappaB. We investigated whether 4-hydroxynonenal (HNE), a prominent aldehyde component of ox-LDL, represents one of the inhibitory substances. NF-kappaB activation by stimuli such as LPS, interleukin (IL)-1beta, and phorbol ester, but not tumor necrosis factor (TNF), was reversibly inhibited by HNE in a dose-dependent manner in human monocytic cells, whereas AP-1 binding was unaffected. Using similar HNE concentrations, LPS-induced kappaB- and TNF or IL-8 promoter-dependent transcription was prevented. Furthermore, pretreatment with HNE suppressed TNF production but not lactate dehydrogenase levels. Under these conditions the binding of LPS to monocytic cells was not significantly affected. However, induced proteolysis of the inhibitory proteins IkappaB-alpha, IkappaB-beta, and, at a later time point, IkappaB-epsilon was prevented. This is not due to inhibition of the proteasome, the major proteolytic activities of which remain unaffected, but rather to a specific prevention of the activation-dependent phosphorylation of IkappaB-alpha. This is the first report which demonstrates that HNE specifically inhibits the NF-kappaB/Rel system. Down-modulation of NF-kappaB-regulated gene expression may contribute at certain stages of atherosclerosis to low levels of chronic inflammation and may also be involved in other inflammatory/degenerative diseases.

Aldehydes↗
PubMed1999

Rel transcription factors contribute to elevated urokinase expression in human ovarian carcinoma cells.

Elevated levels of the urokinase-type plasminogen activator (uPA) in tumor cells are conductive to tumor cell spread and metastasis. In a previous study we observed that suppression of RelA dramatically reduced endogenous uPA synthesis in the human ovarian cancer cell line OV-MZ-6. Because the uPA promoter contains three potential Rel-like protein binding motifs (RRBE, 5'-NF-kappaB, and 3'-NF-kappaB) we conducted the first thorough systematic uPA promoter analysis to examine the direct impact of Rel proteins on uPA gene transcription. Disruption of RRBE resulted in a approximately 40% decrease in uPA promoter activity, mutation of the 5'-NF-kappaB motif led to an additional 20% decrease. The 3'-NF-kappaB motif was not active. Overexpression of RelA significantly enhanced uPA promoter activity, whereas IkappaB-alpha overexpression reduced uPA promoter activity by 40%. These data were supported by the finding that endogenous uPA was also increased sixfold by overexpression of RelA and decreased by 30% upon overexpression of IkappaB-alpha. Transfection of OV-MZ-6 cells with antisense deoxynucleotides directed to RelA expression reduced uPA promoter activity by at least 40%. Our data clearly suggest that by binding to uPA promoter elements, Rel transcripton factors contribute directly to elevated uPA gene expression in human ovarian cancer cells, thereby promoting the multiple functions of uPA during tumor growth and metastasis.

Binding Sites↗
PubMed1999

Tissue factor expression of human monocytes is suppressed by lysophosphatidylcholine.

The expression of tissue factor (TF), the principal initiator of coagulation, is increased during inflammation and atherosclerosis. Both conditions are promoted by lysophosphatidylcholine (lysoPC). We observed in the present study that lysoPC (1 to 10 micromol/L) dose-dependently reduced TF activity in human monocytes, as elicited by lipopolysaccharide (LPS). Lysophosphatidylethanolamine (lysoPE) and other lysophospholipids did not affect LPS-induced TF activity of human monocytes. TF antigen expression as elicited by LPS was also lowered by lysoPC. Phospholipid analyses indicated a selective increase in the lysoPC content of the monocytes after preincubation with the lysophospholipid. LysoPC inhibited the TF activity of Mono Mac-6 cells to a similar extent as in the monocytes. LPS binding to plasma membrane receptors and internalization of LPS into monocytes were not affected by lysoPC. In contrast, LPS-mediated nuclear binding of nuclear factor-kappaB/Rel to a TF-specific kappaB site was inhibited by lysoPC. Induction of TF mRNA expression by LPS tended to be partially reduced by the lysophospholipid. Preincubation with lysoPC increased monocytic cAMP levels. Inhibition of adenylyl cyclase by pretreatment with 2'-deoxy-3'-adenosine monophosphate partially reversed the inhibition of TF activity promoted by lysoPC. In conclusion, lysoPC markedly decreases LPS-mediated TF expression of human monocytes, the effect probably being mediated by both transcriptional and posttranscriptional mechanisms. LysoPC may thus attenuate activation of coagulation during inflammation and atherosclerosis.

Adenylyl Cyclase Inhibitors↗
PubMed1998

Activated platelets induce monocyte chemotactic protein-1 secretion and surface expression of intercellular adhesion molecule-1 on endothelial cells.

BACKGROUND: Platelet/endothelium interaction plays an important role in the pathophysiology of inflammation and atherosclerosis. The role of platelets for monocyte chemotactic protein-1 (MCP-1) secretion and surface expression of intercellular adhesion molecule-1 (ICAM-1) on endothelial cells has been assessed. METHODS AND RESULTS: Monolayers of human umbilical vein endothelial cells were incubated with nonstimulated or ADP-activated platelets for 6 hours, and secretion of MCP-1 and surface expression of ICAM-1 were determined by ELISA and flow cytometry, respectively. In the presence of ADP-activated platelets, both MCP-1 secretion and ICAM-1 surface expression were significantly increased compared with nonstimulated platelets (P<0.02). Activation of the transcription factor nuclear factor-kappaB (NF-kappaB) determined by electrophoretic mobility shift assay and kappaB-dependent transcriptional activity was enhanced in the presence of activated platelets. In addition, ADP-activated platelets induced MCP-1 and ICAM-1 promoter-dependent transcription. Liposomal transfection of a double-stranded kappaB phosphorothioate oligonucleotide, but not of the mutated form, inhibited MCP-1 secretion and surface expression of ICAM-1 on activated endothelium (P<0.05). CONCLUSIONS: The present study indicates that activated platelets modulate chemotactic (MCP-1) and adhesive (ICAM-1) properties of endothelial cells via an NF-kappaB-dependent mechanism. Platelet-induced activation of the NF-kappaB system might contribute to early inflammatory events in atherogenesis.

Arteriosclerosis↗
PubMed1998

Xanthine oxidoreductase in human mammary epithelial cells: activation in response to inflammatory cytokines.

Xanthine oxidoreductase (XOR) in human mammary epithelial cells was shown to have low true specific activity, similar to that in breast milk. Enzymic activity was increased in response to inflammatory cytokines; increases of 2-2.5-fold being seen with TNF-alpha and IL-1beta and of approximately 8-fold with IFN-gamma. No significant increase was seen with IL-6. A combination of IFN-gamma and TNF-alpha, or of these two cytokines plus IL-1beta, led to responses representing the sum of those obtained by using the individual cytokines. The 8-fold increase in enzymic activity, stimulated by IFN-gamma, corresponded to only a 2-3-fold increase in specific mRNA, suggesting the possibility of post-translational activation; a possibility strongly supported by the corresponding 2-3-fold rise in XOR protein, as determined by ELISA. In no case was cytokine-induced activation accompanied by changes in the oxidase-dehydrogenase ratio of XOR. These data strongly support a role for XOR in the inflammatory response of the human mammary epithelial cell, and provide further evidence of post-translational activation of a low activity form of human XOR, similar to that previously observed in vivo for the breast milk enzyme.

Breast↗
PubMed1998

Xanthine oxidoreductase is asymmetrically localised on the outer surface of human endothelial and epithelial cells in culture.

Subcellular localisation of xanthine oxidoreductase (XOR) was determined by indirect immunofluorescence using confocal microscopy in human endothelial and epithelial cell lines and in primary cultures of human umbilical vein endothelial cells. XOR was diffusely distributed throughout the cytoplasm but with higher intensity in the perinuclear region. In non-permeabilised cells, XOR was clearly seen to be asymmetrically located on the outer surfaces, showing, in many cases, a higher intensity on those faces apposed by closely neighbouring cells. Such specific distribution suggests a functional role for the enzyme in cell-cell interactions, possibly involving signalling via reactive oxygen species.

Cell Line↗
PubMed1998

Effect of proteasome inhibitors on monocytic IkappaB-alpha and -beta depletion, NF-kappaB activation, and cytokine production.

We investigated the effect of proteasome inhibitors on the lipopolysaccharide (LPS)-induced expression of several monocytic cytokines, which may be dependent on the transcription factor, nuclear factor-kappaB (NF-kappaB). Exposure of human monocytic THP-1 cells to ALLN and Mu873 prevented the LPS-induced degradation of IkappaB-alpha and -beta, as did the more potent proteasome inhibitor, PSI, whereas several calpain inhibitors were ineffective. This was accompanied by the inhibition of nuclear NF-kappaB binding activity and NF-kappaB transcriptional activation. At the mRNA level, the inhibitors blocked the expression of tumor necrosis factor (TNF) and interleukin-1beta (IL-1beta), whereas IL-8 remained unaffected by ALLN and was only partially reduced by the highest dose of PSI. The latter effect appears to be due to an increase in IL-8 mRNA stability in the presence of proteasome inhibitors. Furthermore, the production of TNF was efficiently suppressed by ALLN and PSI, less by Mu873, and not at all by calpain inhibitors. In primary human blood monocytes ALLN also prevented the LPS-induced degradation of IkappaB-alpha and -beta, efficiently blocked the production of TNF and, to a lesser extent, IL-1beta, whereas that of IL-8 was not inhibited. The expression of NF-kappaB-dependent monocytic cytokines may be selectively controlled by the proteasome, offering a potential therapeutic target in inflammatory disease.

Cell Line↗
PubMed1998

Nuclear factor kappaB is activated in macrophages and epithelial cells of inflamed intestinal mucosa.

BACKGROUND & AIMS: Transcription factors of the nuclear factor kappaB (NF-kappaB) family play an important role in the regulation of genes involved in inflammation. In inflammatory bowel diseases, proinflammatory cytokines known to be regulated by NF-kappaB are involved. The aim of this study was to investigate the role of NF-kappaB activation during mucosal inflammation in situ. METHODS: A monoclonal antibody, alpha-p65mAb, was applied for immunofluorescence and immunohistochemical analysis that recognizes activated NF-kappaB. Electrophoretic mobility shift assay was used to directly demonstrate the presence of active DNA-binding NF-kappaB. RESULTS: Using the alpha-p65mAb antibody, activated NF-kappaB could be found in biopsy specimens from inflamed mucosa but was almost absent in uninflamed mucosa. The number of cells showing NF-kappaB activation correlated with the degree of mucosal inflammation but was not significantly different between inflamed mucosa from patients with Crohn's disease, ulcerative colitis, and nonspecific colitis or diverticulitis. NF-kappaB activation was localized in macrophages and in epithelial cells as identified by double-labeling techniques. Electrophoretic mobility shift assay with isolated lamina propria mononuclear cells and epithelial cells confirmed these results. CONCLUSIONS: This study shows for the first time the activation of NF-kappaB during human mucosal inflammation in situ. In addition to macrophages, epithelial cells contained activated NF-kappaB, indicating an involvement in the inflammatory process.

Adult↗
PubMed1998

Intracellular Mg2+ regulates ADP phosphorylation and adenine nucleotide synthesis in human erythrocytes.

13C- and 31P-NMR were used in methylene blue-treated human erythrocytes to determine the dependence on intracellular Mg2+ concentration ([Mg2+]i) of the pentose phosphate pathway (PPP), the glycolytic pathway, and adenine nucleotide synthesis. The PPP flux had an [Mg2+]i at half-maximal velocity ([Mg2+]i,0.5) of 0.02 mM, well below the physiological range (0.2-0.7 mM). Flux through the PPP was reduced at higher [Mg2+]i as flux through phosphofructokinase was increased ([Mg2+]i,0.5 = 0.16 mM). [Mg2+]i,0.5 of phosphoglycerate kinase flux, which equals net ADP phosphorylation rate, was 0.27 mM, well within the physiological [Mg2+]i range. The rate of adenine nucleotide synthesis from [2-13C]glucose-derived ribose 5-phosphate and exogenous adenine also exhibited dependence on [Mg2+]i but was not saturable up to 1.6 mM. Therefore, net flux through the PPP and glycolytic pathways in erythrocytes is not strongly dependent on [Mg2+]i at physiological ion concentrations, but both ADP phosphorylation and adenine nucleotide synthesis are likely to be regulated by normal fluctuations in [Mg2+]i.

Adenine Nucleotides↗
PubMed1998

Accepting the gay person: rental accommodation in the community.

Effects of the "homosexual" label in obtaining community accommodation were examined, in a sample of 180 individuals advertising rooms or flats for rent in two Canadian cities, Windsor and London, Ontario, and in Detroit, Michigan. Telephone calls, for half the sample, made simple enquiries as to availability; for the other half, similar enquiries were made by an individual who was ostensibly homosexual. In the latter condition, rooms were significantly more likely to be described as unavailable. Comparisons are made to similar, previous research, and to current perspectives about community reactions to stigmatizing conditions.

Canada↗
PubMed1997

Role of nuclear factor-kappa B in atherogenesis.

Transcription factors of the nuclear factor-kappa B (NF-kappa B)/Rel family have an important function in the regulation of a variety of genes involved in the inflammatory and proliferative responses of cells. Recent studies strongly indicate that the inducible transcription factor NF-kappa B is involved in the pathogenesis of atherosclerosis. Activated NF-kappa B is present in the fibrotic thickened intima-media and atheromatous areas of the atherosclerotic lesion, within smooth muscle cells, macrophages and endothelial cells, whereas little or no activated NF-kappa B can be detected in vessels lacking atherosclerosis. A variety of molecules have been identified in the atherosclerotic environment that are able to activate NF-kappa B in vitro. Furthermore, an increased expression of numerous genes known to be regulated by NF-kappa B has been found in the atherosclerotic lesion. Possible functional implications for activated NF-kappa B in atherogenesis are discussed here. The activation and role of NF-kappa B in atherosclerosis may provide a model for the involvement of the transcription factor in human chronic inflammatory disease.

Animals↗
PubMed1997

Dysregulation of monocytic nuclear factor-kappa B by oxidized low-density lipoprotein.

Nuclear factor-kappa B (NF-kappa B)/Rel transcription factors may be involved in atherosclerosis, as is suggested by the presence of activated NF-kappa B in human atherosclerotic lesions. The aim of the present study was to investigate the effects of oxidized LDL (oxLDL) on the NF-kappa B system in human THP-1 monocytic cells as well as adherent monocytes. Our results demonstrate that short-term incubation of these cells with oxLDL activated p50/p65 containing NF-kappa B dimers and induced the expression of the target gene IL-8. This activation of NF-kappa B was inhibited by the antioxidant and H2O2 scavenger pyrrolidine dithiocarbamate and the proteasome inhibitor PSI. The oxLDL-induced NF-kappa B activation was accompanied by an initial depletion of I kappa B-alpha followed by a slight transient increase in the level of this inhibitor protein. In contrast, long-term treatment with oxLDL prevented the lipopolysaccharide-induced depletion of I kappa B-alpha, accompanied by an inhibition of both NF-kappa B activation and the expression of tumor necrosis factor-alpha and interleukin-1 beta genes. These observations provide additional evidence that oxLDL is a potent modulator of gene expression and suggest that (dys)regulation of NF-kappa B/Rel is likely to play an important role in atherogenesis.

Antioxidants↗
PubMed1997

Perception of medical symptoms according to gender of reporting person and type of symptom.

Two hundred and eight male and female participants were given unanticipated memory and recognition tasks with which to recall and recognize medical symptoms, described on audiotapes by male and female individuals. Half of the presented symptoms were among those typically experienced by males; half were among those experienced mostly by females. Both memory and recall were better when the audiotaped reporting persons was male. Gender orientation of symptoms (male versus female orientation) was not associated with better recall or recognition, nor was the factor of subject gender. Although neither "male" nor "female" symptoms were seen generally as more serious overall, an interaction effect showed that symptoms were seen as more serious, especially in the case of the male audiotape, when they were incongruous with the gender of the reporting person. Some possible implications of the results are outlined. More research is required to assess the differential perception of medical and other types of symptoms.

Adult↗