Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The human herpesvirus 6 (HHV-6) is known to interact intimately with cells of the immune system. Here we report that HHV-6 is a potent inducer of interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha) in cultures of peripheral blood mononuclear cells. In contradistinction, HHV-6 has no effect on IL-6 synthesis. Maximal IL-1 beta and TNF-alpha gene transcription, as detected by polymerase chain reaction amplification analysis, is observed at 12 and 6 h postinfection, respectively. Release of IL-1 beta and TNF-alpha into the culture supernatants peaked at 24 h and gradually decreased with time. Heat-inactivated virus was unable to stimulate IL-1 beta and TNF-alpha syntheses, whereas UV-irradiated virus retained the full monokine-inducing potential of the native particle. Preincubation of viral preparation with neutralizing anti-HHV-6 antibody resulted in the abrogation of this cytokine-inducing effect, whereas treatment of cells with phosphonoacetic acid (an inhibitor of viral DNA polymerase activity) had no effect on the ability of the virus to stimulate monokine release. These results indicate that HHV-6 can exert a strong immunomodulatory effect by stimulating the cells of myeloid lineage to produce these cytokines.
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PMID:Human herpesvirus 6 induces interleukin-1 beta and tumor necrosis factor alpha, but not interleukin-6, in peripheral blood mononuclear cell cultures. 165 26

In a previous study, we revealed that tumor necrosis factor (TNF) was secreted in mouse liver at an early phase of liver regeneration after partial hepatectomy. Here, we investigated direct actions of TNF on the in vitro DNA synthesis of adult mouse hepatocytes in primary culture. TNF enhanced both 3H-TdR uptake and the number of 3H-TdR-labeled nuclei of hepatocytes. Their time courses were similar to those by epidermal growth factor (EGF) with about a 15 h lag period and a peak period of 24-48 h. This action of TNF was abrogated by DNA polymerase alpha inhibitor, aphidicolin and blocked specifically by anti-TNF antibody. The actions of rmTNF and rhTNF were not distinguishable; ED50 was about 7.5U/ml (5ng/ml) and 30U/ml (20ng/ml) for maximal response (about 2-fold or more of control). Other inflammatory monokines showed differential effects on in vitro DNA synthesis of hepatocyte. Neither type of interleukin 1 affected hepatocyte DNA synthesis in the range examined (up to 50 ng/ml). IL-6 markedly inhibited the hepatocyte DNA synthesis stimulated by TNF and EGF. The action of TNF was completely suppressed by transforming growth factor beta, which is known as a potent inhibitor of hepatocyte growth. Interferon gamma also blocked this TNF action when added simultaneously. These results indicate that the activation of tissue macrophages and local secretion of TNF in liver after partial hepatectomy is of physiological importance in liver regeneration, in part by a direct stimulation of hepatocyte DNA synthesis. Cytokines induced by TNF may also participate in the later termination of liver regeneration.
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PMID:Tumor necrosis factor stimulates DNA synthesis of mouse hepatocytes in primary culture and is suppressed by transforming growth factor beta and interleukin 6. 173 Jul 79

Lentinan, a beta-1,6;1,3-glucan, is tumor-specific for transplantable mouse solid-type tumors and it also stimulates the production of acute phase proteins (APPs). The APP response to lentinan is of the delayed type (DT-APR) and differs from that to lipopolysaccharide, which is acute. We found that the responses were genetically controlled in mice and that low responsiveness is dominant (Maeda et al. 1991). Using 123 segregants of crosses between SWR/J (a high responder) and Mus spretus (a low responder), we analyzed the linkage between DT-APR responsiveness and the DNA polymerase chain reaction-simple sequence length polymorphism (PCR-SSLP) phenotype using 80 chromosome-specific microsatellite markers. We identified two loci (ltn1.1 and ltn1.2) responsible for DT-APR. ltn1.1 is closely linked to D3Mit11 on chromosome 3 and ltn1.2 to D11Nds9 on chromosome 11 (P <0.001). The linkage analysis also suggested that ltn1.2 is the major determinant for DT-APR. Correlation between lentinan-specific IL-6 mRNA expression (the late expression) controlled recessively and DT-APR induction suggests that the ltn1 loci control some process(es) of IL-6 expression in the regulation step before NF-IL6.
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PMID:Two genes controlling acute phase responses by the antitumor polysacch aride, lentinan. 857 20

Stem cell factor (SCF) is known to act synergistically with other hematopoietic factors in increasing the colony formation of hematopoietic progenitor cells. We have shown that interleukin-3 (IL-3)-dependent proliferation of NFS-60 cells is associated with the induction of a specific calmodulin-binding protein of about 68 kD (CaM-BP68). To evaluate the relationship between proliferative stimulation and the induction of CaM-BP68 by cytokines, we examined whether the increased proliferative potential of NFS-60 cells in response to SCF is reflected in an increased induction of the CaM-BP68. We observed that SCF alone has a limited effect on proliferative stimulation and on the induction of CaM-BP68 in factor-deprived NFS-60 cells. However, when combined with IL-3, granulocyte colony-stimulating factor (G-CSF), or IL-6, it caused a significant increase in cytokine-dependent proliferative stimulation, as well as in the induction of CaM-BP68. Furthermore, an increase in IL-3-dependent induction of CaM-BP68 in the presence of SCF coincided with a corresponding increase in thymidine kinase activity, whose expression is linked to G1/S transition of the cells. At low concentrations SCF caused a synergistic increase in IL-3-dependent induction of both CaM-BP68 and thymidine kinase activity. In contrast to the changes in CaM-BP68 and thymidine kinase activity, no significant changes in DNA polymerase alpha were observed in factor-deprived NFS-60 cells in response to IL-3 and/or SCF. These observations suggest an increased expression of CaM-BP68 and thymidine kinase are associated with the synergistic effect of SCF on factor-dependent proliferation of hematopoietic progenitor cells.
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PMID:Stem cell factor enhances interleukin-3 dependent induction of 68-kD calmodulin-binding protein and thymidine kinase activity in NFS-60 cells. 860 34

Our previous work in patients undergoing autologous transplant for multiple myeloma (MM) or breast cancer (BC) has shown that retroviral transduction of adult CD34+ cells for 72 hours in the presence of interleukin-3 (IL-3), IL-6, and stem cell factor (SCF) resulted in .01% to 1% long-term marking of peripheral blood and marrow cells (Blood 85:3948, 1995). In this study we compare these previous studies to transduction with no added growth factors, previously shown to result in higher levels of marking in children (Lancet 342:1134, 1993) or transduction in the presence of an autologous stromal layer. Peripheral blood (PB) mononuclear cells were collected via apheresis after high-dose cyclophosphamide and granulocyte colony-stimulating factor. Bone marrow (BM) was also harvested in all patients. One third of both BM and PB collections were enriched for CD34+ cells and transduced with one of two marking vectors containing the neomycin-resistance gene to distinguish cells originating from BM and PB posttransplantation. Cells from 3 MM and 2 BC patients were transduced without growth factors for 6 hours and cells from 2 MM and 2 BC patients were transduced in the presence of autologous marrow stroma. Immediately posttransduction, the percentage of Neo-resistant PB and BM progenitors (colony-forming units) were: 0% to 19% in the 6-hour no growth factor group and 0% to 36% in the autologous stroma group. After conditioning therapy, both transduced and untransduced PB and BM fractions were infused into the patients. Semi-quantitative nested DNA polymerase chain reaction was performed on total, mononuclear, and granulocyte fractions of PB and BM at 1, 3, 6, 9, 12, and 18 months. Poor marking has been observed in both groups, with no consistently positive patients. These results compare unfavorably with our prior experience using growth factors during transduction. Further optimization of transduction conditions and vectors needs to be developed to improve transduction efficiency of adult human repopulating hematopoietic cells.
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PMID:Retroviral gene transduction of adult peripheral blood or marrow-derived CD34+ cells for six hours without growth factors or on autologous stroma does not improve marking efficiency assessed in vivo. 916 43

It is well known that EBV has developed strategies to evade immune surveillance. Previously, EBV was shown to bind specifically to monocytes and regulate expression of proinflammatory mediators such as IL-1, IL-6, TNF-alpha, and leukotrienes. EBV was also found to affect phagocytosis of monocytes. In this study, we show that in addition to these effects, EBV suppresses the biosynthesis of PGE2, a pleiotropic immunomodulatory molecule that is synthesized by the dioxygenation of arachidonic acid via the cyclooxygenase (COX) pathway. This down-regulation of PGE2 formation involved the inhibition of the inducible COX-2 isoform expression both at the transcriptional and translational levels, whereas expression of the constitutive COX-1 isoform was unaltered. Furthermore, exposure of monocytes to EBV was found to impact on the NF-kappaB activation pathway, which plays an essential role in the induction of COX-2 in monocytes. The inhibition of PGE2 biosynthesis was relieved when the experiments were conducted in presence of phosphonoacetic acid, an inhibitor of herpesviruses DNA polymerase, indicating that viral replication and/or neosynthesized viral proteins were involved in this process. Thus, inhibition of PGE2 biosynthesis in monocytes may represent an additional mechanism underlying EBV pathogenicity.
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PMID:EBV suppresses prostaglandin E2 biosynthesis in human monocytes. 1084 3

Here we present a novel methodology to quantitate bovine cytokines and growth factors contributing to immunity against bacterial infections of the mammary gland in cattle. Real-time TaqMan PCR systems were developed to overcome limitations of conventional quantitative PCR methods. The TaqMan method is based on the cleavage of fluorescent dye-labeled probes by the 5'-3' exonuclease activity of the Taq DNA polymerase during PCR and measurement of fluorescence intensity by an automated spectrophotometer integrated in a sequence detection system (Applied Biosystems, Foster City, CA). The bovine-specific TaqMan probes were designed to encompass an intron, thus allowing differentiation between complementary DNA (cDNA) and genomic DNA (gDNA) amplification products. Quantitative analysis of cytokine cDNA was performed in comparison to bovine glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Messenger RNA (mRNA) from the universally expressed housekeeping gene GAPDH proved to be useful as an amplification control and allowed for correction of variations in different numbers of cells in the starting material, in the efficiencies of RNA extraction and reverse transcription. With this method, high-throughput analysis of large numbers of samples was possible within a short time. In addition, decreasing the numbers of working steps shortened the time for analysis and increased accuracy. Profiles of cytokines (interleukin (IL)-2, IL-6, IL-8, IL-12 p40, TNF-alpha, IFN-gamma) and granulocyte-macrophage colony stimulating factor (GM-CSF) were established in normal lactating cattle. Differences of cytokine profiles obtained with the real-time TaqMan PCR system and conventional methods are discussed.
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PMID:Quantitation of bovine cytokine mRNA in milk cells of healthy cattle by real-time TaqMan polymerase chain reaction. 1113 25

Kaposi's sarcoma-associated herpesvirus (KSHV), the most recently discovered human tumour virus, is the causative agent of Kaposi's sarcoma, primary effusion lymphoma and some forms of Castleman's disease. KSHV is a rhadinovirus, and like other rhadinoviruses, it has an extensive array of regulatory genes obtained from the host cell genome. These pirated KSHV proteins include homologues to cellular CD21, three different beta-chemokines, IL-6, BCL-2, several different interferon regulatory factor homologues, Fas-ligand ICE inhibitory protein (FLIP), cyclin D and a G-protein-coupled receptor, as well as DNA synthetic enzymes including thymidylate synthase, dihydrofolate reductase, DNA polymerase, thymidine kinase and ribonucleotide reductases. Despite marked differences between KSHV and Epstein-Barr virus, both viruses target many of the same cellular pathways, but use different strategies to achieve the same effects. KSHV proteins have been identified which inhibit cell-cycle regulation checkpoints, apoptosis control mechanisms and the immune response regulatory machinery. Inhibition of these cellular regulatory networks app ears to be a defensive means of allowing the virus to escape from innate antiviral immune responses. However, due to the overlapping nature of innate immune and tumour-suppressor pathways, inhibition of these regulatory networks can lead to unregulated cell proliferation and may contribute to virus-induced tumorigenesis.
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PMID:Molecular virology of Kaposi's sarcoma-associated herpesvirus. 1131 14

Methionine deprivation imposes a metabolic stress, termed methionine stress, that inhibits mitosis and induces cell cycle arrest and apoptosis. The methionine-dependent central nervous system tumor cell lines DAOY (medulloblastoma), SWB61 (anaplastic oligodendroglioma), SWB40 (anaplastic astrocytoma), and SWB39 (glioblastoma multiforme) were compared with methionine-stress resistant SWB77 (glioblastoma multiforme). The cDNA-oligoarray analysis and reverse transcription-PCR verification indicated common changes in gene expression in methionine-dependent cell lines to include up-regulation/induction of cyclin D1, mitotic arrest deficient (MAD)1, p21, growth arrest and DNA-damage-inducible (GADD)45 alpha, GADD45 gamma, GADD34, breast cancer (BRCA)1, 14-3-3sigma, B-cell CLL/lymphoma (BCL)1, transforming growth factor (TGF)-beta, TGF-beta-induced early response (TIEG), SMAD5, SMAD7, SMAD2, insulin-like growth factor binding protein (IGFBP7), IGF-R2, vascular endothelial growth factor (VEGF), TNF-related apoptosis-inducing ligand (TRAIL), TNF-alpha converting enzyme (TACE), TRAIL receptor (TRAIL-R)2, TNFR-related death receptor (DR)6, TRAF interacting protein (I-TRAF), IL-6, MDA7, IL-1B convertase (ICE)-gamma, delta and epsilon, IRF1, IRF5, IRF7, interferon (IFN)-gamma and receptor components, ISG15, p65-NF-kappaB, JUN-B, positive cofactor (PC)4, C/ERB-beta, inositol triphosphate receptor I, and methionine adenosyltransferase II. On the other hand, cyclins A1, A2, B1 and B2, cell division cycle (CDC)2 and its kinase, CDC25 A and B, budding uninhibited by benzimidazoles (BUB)1 and 3, MAD2, CDC28 protein kinase (CKS)1 and 2, neuroepithelial cell transforming gene (NET)1, activator of S-phase kinase (ASK), CDC14B phosphatase, BCL2, TGF-beta activated kinase (TAK)1, TAB1, c-FOS, DNA topoisomerase II, DNA polymerase alpha, dihydrofolate reductase, thymidine kinase, stathmin, and MAP4 were down-regulated. In the methionine stress-resistant SWB77, only 20% of the above genes were affected, and then only to a lesser extent. In addition, some of the changes observed in SWB77 were opposite to those seen in methionine-dependent tumors, including expression of p21, TRAIL-R2, and TIEG. Despite similarities, differences between methionine-dependent tumors were substantial, especially in regard to regulation of cytokine expression. Western blot analysis confirmed that methionine stress caused the following: (a) a marked increase of GADD45alpha and gamma in the wt-p53 cell lines SWB61 and 40; (b) an increase in GADD34 and p21 protein in all of the methionine-dependent lines; and (c) the induction of MDA7 and phospho-p38 in DAOY and SWB39, consistent with marked transcriptional activation of the former under methionine stress. It was additionally shown that methionine stress down-regulated the highly active phosphatidylinositol 3'-kinase pathway by reducing AKT phosphorylation, especially in DAOY and SWB77, and also reduced the levels of retinoblastoma (Rb) and pRb (P-ser780, P-ser795, and P-ser807/811), resulting in a shift in favor of unphosphorylated species in all of the methionine-dependent lines. Immunohistochemical analysis showed marked inhibition of nuclear translocation of nuclear factor kappaB under methionine stress in methionine-dependent lines. In this study we show for the first time that methionine stress mobilizes several defined cell cycle checkpoints and proapoptotic pathways while coordinately inhibiting prosurvival mechanisms in central nervous system tumors. It is clear that methionine stress-induced cytotoxicity is not restricted by the p53 mutational status.
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PMID:Modulation of gene expression in human central nervous system tumors under methionine deprivation-induced stress. 1549 78

Posttransplantation alloantigen-dependent and alloantigen-independent processes are both mediated by cytokines and chemokines. Recently cytokines and chemokines, as well as their receptors, have been shown to be highly polymorphic. The cytokine and chemokine gene polymorphisms are associated with variable production, activity, expression, or ligand-receptor affinity. The aim of our study was to analyze the relation between selected cytokine and chemokine gene polymorphisms in kidney donors and recipients as a function of donor-recipient match and posttransplantation outcome. Polymorphisms transforming growth factor-beta (TGF-beta); tumor necrosis factor-alpha (TNF-alpha); interleukin (IL)-6, and IL-10; monocyte chemoattractant protein-1 (MCP-1); and RANTES (regulated upon activation, normal T-cell expressed and secreted) genes were determined using DNA polymerase chain reaction technology in 268 healthy volunteers, 345 kidney transplant recipients (1997 to 1999), and 298 cadaveric donors. Patients were followed up for 4 to 6 years. The distribution of alleles of selected genes was identical in control subjects, cadaveric donors, and recipients. Low TGF-beta production in both the donor and recipient genotypes was associated with risk for early rejection (6 months) and worse graft function at 4 years. The only tendency for worse graft outcome was observed among donor-recipient combinations mismatched for TGF-beta genotype. Genetic determination of TNF-alpha and IL-10 production was associated with delayed graft function and rejection. IL-6 gene polymorphisms had no effect on the incidence of early acute rejections, but was associated with worse 5-year outcomes. Determinations of MCP-1 overproduction and RANTES-109 TT allele were associated with significant deterioration of graft function. Our data support the hypothesis that the strength of the alloimmune response after transplantation is in part genetically determined. Donor-recipient matching of cytokine gene polymorphisms has a marginal effect.
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PMID:Effect of cytokines and chemokines (TGF-beta, TNF-alpha, IL-6, IL-10, MCP-1, RANTES) gene polymorphisms in kidney recipients on posttransplantation outcome: influence of donor-recipient match. 1584 24


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