No abstract available.
Mass Screening* ; src Homology Domains*

No abstract available.
Ethanol*

No abstract available.
Cell Cycle*

The cytolytic activity of CD4' T cells, both human and murine, has been clearly demonstrated in the immune response to mycobacterial infection and suggested to play a significant role in the protection and immunopathology. However, Uttle is known about the differentiation of CD4' CTL. In order to address this issue, we examined the influences of some factors on the generation of CD4' CTL specific to mycobacterial antigens. After 7 days' stimulation of PBMCs from healthy tuberculin reactors with mycobacterial antigens, the cytolytic activity of purised CD4' T cells toward autologous macrophages infected with mycobacteria was measured by Cr release assay. First, we found that both of live M. tubeiculosis and soluble antigens (ST-CF) induced the cytolytic activity of CD4' T cells, although the inducibility of the former was slightly greater than the latter. Second, the cytolytic activity was maximally induced at the relatively low antigen concentration (0.2:1 bacteria:monocyte ratio or 0.5 mg/ml of ST-CF). Finally, in the presence of increasing amounts of neutralizing anti-IL-12 or anti-IFN-r MoAb, the cytolytic activity of CD4+ T cells was decreased in a dose-dependent manner. These results suggest that low dose of antigen, its particulate type give mycobacteria), IL-12, and IFN-r give some positive signals for the generation of CD4+ CTL.
Humans ; Interleukin-12 ; Macrophages ; T-Lymphocytes* ; Tuberculin

TNF-alpha, a trimeric cytokine, was known to inhibit differention of preadipocytes to adipocytes. In the present study, we investigated signal mediators working downstream of TNF-alpha using murine 3T3-L1 cells. TNF-alpha induced activation of both c-jun NH2-terminal kinase (JNK) and nuclear transcription factor-kappaB (NF-kappaB) in 3T3-L1 cells. Blockage of these two mediators activities by specific inhibitors, SP600125 and Ad-IkappaBalpha-SR restored adipogenesis differentiation suggesting their involvement in the inhibited differentiation of 3T3-L1 cells by TNF-alpha. Consistent with previous studies, peroxisome proliferator-activated receptor gamma (PPARgamma) a key transcriptional regulator was remarkably reduced by TNF-alpha treatment. Compared with adipogenesis, however, SP600125, a chemical JNK inhibitor hardly relieved TNF-alpha effect on PPARgamma expression whereas S32A/S36A mutant of IkappaBalpha considerably recovered PPARgamma expression, indicating that two signal mediators exploit separable main routes to achieve reduced adipogenesis. These results suggest that inhibition of 3T3-L1 cells differentiation by TNF-alpha is partly implemented through NF-kappaB and one of its downstream effectors be PPARgamma.
3T3-L1 Cells ; Adipocytes/cytology/drug effects ; Animals ; Cell Differentiation/*drug effects ; Gene Expression Regulation/*drug effects ; Mice ; NF-kappa B/*metabolism ; Promoter Regions (Genetics)/genetics ; RNA, Messenger/genetics/metabolism ; Receptors, Cytoplasmic and Nuclear/*genetics ; Support, Non-U.S. Gov't ; Transcription Factors/*genetics ; Tumor Necrosis Factor/*pharmacology

Glucocorticoid receptor (GR) functions as a suppressor of inflammation by inhibiting the expression of many cytokine gene activated by NF-κB. The goal of this study is to investigate the mechanism by which GR repress NF-κB activation in lung epithelial cells. We used A549 and BEAS-2B lung epithelial cell lines. Using IgGκ-NF-κB luciferase reporter gene construct, we found that dexamethasone significantly suppressed TNF-α-induced NF-κB activation and the overexpression of GR showed dose-dependent reduction of TNF-α-induced NF-κB activity in both cell lines. However, DNA binding of NF-κB induced by TNF-α in electromobility shift assay was not inhibited by dexamethasone. Super shift assay with anti-p65 antibody demonstrated the existence of p65 in NF-κB complex induced by TNF-α Western blot showed that IκBα degradation induced by TNF-α was not affected by dexamethasone and IκBκ was not induced by dexamethasone, neither. To evaluate p65 specific transactivation, we adopted co-transfection study of Ga14-p65TA1 or TA2 fusion protein expression system together with 5xGa14-luciferase vector. Co-transfection of GR with Ga14-p65TA1 or TA2 repressed luciferase activity profoundly to the level of 10-20% of p65TA1- or TA2-induced transcriptional activity. And this transrepressional effect was abolished by co-transfection of CBP or SRC-1 expression vectors. These results suggest that Gr-mediated transrepression of NF-κB in lung epithelial cells is through competing for binding to limiting amount of transcriptional coactivators, CBP or SRC-1.
Blotting, Western ; Cell Line ; Dexamethasone* ; DNA ; Epithelial Cells* ; Genes, Reporter ; Inflammation ; Luciferases ; Lung ; NF-kappa B* ; Receptors, Glucocorticoid ; Transcriptional Activation*

To investigate the interaction of stimulatory GTP binding protein (G(s)) pathways with others, we overexpressed wild type alpha subunit of G(s) (G(s) alpha), constitutively activated R201E G(s) alpha, and dominant negative G226A G(s) alpha in COS-1 cells by transfection with DEAE-dextran, respectively, The expression of various G proteins in the transfected cells was analyzed after 72 h by quantitative Western blots, and cAMP production by stimulation with isoproterenol and forskolin was quantitated using cAMP binding proteins, The expression of Gs alpha increased about 5-fold in the transfected cells, with concomitant increase in the small forms. However, there was no significant alteration the in the level of the alpha subunit of inhibitory G protein (G(i)) and G(q), and the beta subunits of G proteins. The cAMP level without stimulation increased in the cells transfected with G(s) alpha regardless to the type of mutation, Treatment with either isoproterenol or forskolin resulted in comparable increase of the cAMP level in all the transfected cells, though the ratio to its respective basal level was smaller in the G(s) alpha-transfected cells, From this experiment, we found that the expression of the other G proteins and the signaling pathway producing cAMP did not change significantly by transiently expressing wild type, constitutively activated type, and dominant negative type of G(s) alpha. Analysis of the effects of long-term expression of Gs alpha would contribute to better understanding on how the G(s) alpha signaling system interacts with other signaling pathways and how it adapts to the changed environments.
Animals ; Blotting, Western ; Carrier Proteins ; Colforsin ; COS Cells* ; Cyclic AMP ; DEAE-Dextran ; GTP-Binding Proteins* ; Isoproterenol ; Protein Engineering ; Recombinant Proteins ; Transfection

BACKGROUND: NF-κB is the most important transcriptional factor in Il-8 gene expression. Triptolide is a new compound that recently has been shown to inhibit NF-κB activation. The purpose of this study is to investigate how triptolide inhibits NF-κB-dependent IL-8 gene transcription in lung epithelial cells and to pilot the potential for the clinical application of triptolide in inflammatory lung diseases. METHODS: A549 cells were used and triptolide was provided from Pharmagenesis Company (Palo Alto, CA). In order to examine NF-κB-dependent IL-8 transcriptional activity, we established stable A549 IL-8-NF-κB-luc. cells and performed luciferase assays. IL-8 gene expression was measured by RT-PCR and ELISA. A Western blot was done for the study of IκBα degradation and as electromobility shift assay was done to analyze NF-κB DNA binding. p65 specific transactivation was analyzed by a cotransfection study using a Gal4-p65 fusion protein expression system. To investigate the involvement of transcriptional coactivators, we perfomed a transfection study with CBP and SRC-1 expression vectors. RESULTS: We observed that triptolide significantly suppresses NF-κB-dependent IL-8 transcriptional activity induced by IL-1β and PMA. RT-PCR showed that triptolide represses both IL-1β- and pMA-induced IL-8 mRNA expression and ELISA confirmed this triptolide-mediated IL-8 suppression at the protein level. However, triptolide did not affect IκBα degradation and NF-κB DNA binding. In a p65-specific transactivation study, triptolide significantly suppressed Gal4-p65TA1 and Gal4-p65TA2 activity suggesting that triptolide inhibits NF-κB activation by inhibiting p65 transactivation. However, this triptolide-mediated inhibition of p65 transactivation was not rescued by the overexpression of CBP or SRC-1, thereby excluding the role of transcriptional coactivators. CONCLUSIONS: Triptolide is a new compound that inhibits NF-κB-dependent IL-8 transcriptional activation by inhibiting p65 transactivation, but not by an IκBα-dependent mechanism. This suggests that triptolide may have a therapeutic potential for inflammatory lung diseases.
Blotting, Western ; DNA ; Enzyme-Linked Immunosorbent Assay ; Epithelial Cells* ; Gene Expression ; Interleukin-8* ; Luciferases ; Lung Diseases ; Lung* ; NF-kappa B* ; RNA, Messenger ; Transcriptional Activation ; Transfection

Increased expression of a number of proinflammatory genes, including IL-8, is associated with inflammatory conditions such as asthma. Glucocorticoid receptor (GR)beta, one of the GR isoforms, has been suggested to be upregulated in asthma associated with glucocorticoid insensitivity and to work as a dominant negative inhibitor of wild type GRalpha. However, recent data suggest that GRbeta is not a dominant negative inhibitor of GRalpha in the transrepressive process and has its own functional role. We investigated the functional role of GRbeta expression in the suppressive effect of glucocorticoids on tumor necrosis factor (TNF)-alpha-induced IL-8 release in an airway epithelial cell line. GRbeta expression was induced by treatment of epithelial cells with either dexamethasone or TNF-alpha. GRbeta was able to inhibit glucocorticoid-induced transcriptional activation mediated by binding to glucocorticoid response elements (GREs). The suppressive effect of dexamethasone on TNF-alpha-induced IL-8 transcription was not affected by GRbeta overexpression, rather GRbeta had its own weak suppressive activity on TNF-alpha-induced IL-8 expression. Overall histone deacetylase activity and histone acetyltransferase activity were not changed by GRbeta overexpression, but TNF-alpha-induced histone H4 acetylation at the IL-8 promoter was decreased with GRbeta overexpression. This study suggests that GRbeta overexpression does not affect glucocorticoid-induced suppression of IL-8 expression in airway epithelial cells and GRbeta induces its own histone deacetylase activity around IL-8 promoter site.
Acetylation ; Cell Line, Tumor ; Dexamethasone/pharmacology ; Epithelial Cells/metabolism ; *Gene Expression Regulation ; Histones/*metabolism ; Humans ; Interleukin-8/*genetics/metabolism ; Receptors, Glucocorticoid/genetics/*metabolism ; Transcriptional Activation ; Transfection ; Tumor Necrosis Factor-alpha/*antagonists & inhibitors/pharmacology

Increased expression of a number of proinflammatory genes, including IL-8, is associated with inflammatory conditions such as asthma. Glucocorticoid receptor (GR)beta, one of the GR isoforms, has been suggested to be upregulated in asthma associated with glucocorticoid insensitivity and to work as a dominant negative inhibitor of wild type GRalpha. However, recent data suggest that GRbeta is not a dominant negative inhibitor of GRalpha in the transrepressive process and has its own functional role. We investigated the functional role of GRbeta expression in the suppressive effect of glucocorticoids on tumor necrosis factor (TNF)-alpha-induced IL-8 release in an airway epithelial cell line. GRbeta expression was induced by treatment of epithelial cells with either dexamethasone or TNF-alpha. GRbeta was able to inhibit glucocorticoid-induced transcriptional activation mediated by binding to glucocorticoid response elements (GREs). The suppressive effect of dexamethasone on TNF-alpha-induced IL-8 transcription was not affected by GRbeta overexpression, rather GRbeta had its own weak suppressive activity on TNF-alpha-induced IL-8 expression. Overall histone deacetylase activity and histone acetyltransferase activity were not changed by GRbeta overexpression, but TNF-alpha-induced histone H4 acetylation at the IL-8 promoter was decreased with GRbeta overexpression. This study suggests that GRbeta overexpression does not affect glucocorticoid-induced suppression of IL-8 expression in airway epithelial cells and GRbeta induces its own histone deacetylase activity around IL-8 promoter site.
Acetylation ; Cell Line, Tumor ; Dexamethasone/pharmacology ; Epithelial Cells/metabolism ; *Gene Expression Regulation ; Histones/*metabolism ; Humans ; Interleukin-8/*genetics/metabolism ; Receptors, Glucocorticoid/genetics/*metabolism ; Transcriptional Activation ; Transfection ; Tumor Necrosis Factor-alpha/*antagonists & inhibitors/pharmacology