Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vascular endothelial growth factor is a powerful mitogen for endothelial cells, recently reported to be produced by keratinocytes. In the present work, we examined human keratinocytes in primary culture for the splice variants of vascular endothelial growth factor. In situ hybridization revealed that 100% of cultured human keratinocytes expressed mRNA for this cytokine, and analysis by reverse transcriptase-polymerase chain reaction indicated that three species of mRNA were produced. Southern hybridization and size calculations of PCR products revealed mRNA species corresponding to 121, 165, and 189 amino-acid forms of this cytokine. Using a rabbit anti-vascular endothelial growth factor antiserum, we radioimmunoprecipitated two molecular weight forms (approximately 45 and 58 kDa, non-reducing conditions) from keratinocyte culture supernatants. Under reducing conditions, three bands of approximately 15, 20, and 24 kDa appeared, corresponding with the predominant forms of vascular endothelial growth factor described. We propose that secretion of vascular endothelial growth factor by human keratinocytes in vivo sustains angiogenesis during physiologic tissue repair and in pathologic states accompanied by neovascularization.
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PMID:Human keratinocytes express the three major splice forms of vascular endothelial growth factor. 779 44

Human monocyte-derived macrophages (MDM) were infected with the viral strain HIV1/Ba-L and with the clinical isolates HIV1/DAS and HIV1/PAR. Kinetics of tumour necrosis factor alpha (TNF alpha) and interleukin-6 (IL6) production were investigated for 28 days after infection. At the early stages of infection we observed significant TNF alpha and IL6 secretion 2 to 10 h after infection, whatever the viral strain we used. During the late events of MDM infection, TNF alpha and IL6 were detected over 16 to 21 days following HIV1 infection, at the time of high viral replication. Pretreatment of MDM with a TNF alpha synthesis inhibitor, RP 55778, 4 h prior to HIV infection induced a modified cytokine pattern during the first ten hours of infection: TNF alpha production was totally inhibited despite comparable amounts of IL6. At the late phases of the cell culture, a decrease in magnitude of both viral and cytokine production as well as a delay in the appearance of reverse transcriptase activity and cytokine secretion peaks were observed in RP-55778-pretreated and HIV1-infected MDM cultures. Similar results were obtained after pretreatment of HIV1/DAS-infected MDM cultures with an anti-TNF alpha monoclonal antibody.
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PMID:Treatment of human monocyte-derived macrophages with a TNF alpha synthesis inhibitor prior to HIV1 infection: consequences on cytokine production and viral replication. 780 Sep 46

Cytokines are now considered as constitutive factors of the brain. Some of them are involved in the mechanism regulating lineage commitment and cellular differentiation of the central nervous system (CNS). We describe here the analysis of gene expression in cortex and hippocampus, of interleukin-1 alpha (IL1), interleukin-2 (IL2), interleukin-6 (IL6), macrophage-colony stimulating factor-1 (MCSF) and monocyte chemoattractant protein-1 (MCP1) in fetal (day 18 of gestation; G18), newborn (postnatal day 2; P2), young (postnatal day 21; P21) and adult rat using the reverse transcriptase-polymerase chain reaction (RT-PCR). IL6 and MCP1 mRNA presented distinct patterns of expression levels: IL6 mRNA level is most highly expressed in the embryonic cortex, whereas MCP1 is expressed at a maximal level in the postnatal day 2 cortical area. In the hippocampus, IL6 is most expressed at the adult stage and MCP1 exhibits an equal level of expression from day two to the adult stage. However, under our experimental conditions, IL1 alpha, IL2 and MCSF mRNA were not observed. Thus, certain cytokine genes, each with a specific pattern, are expressed in the rat CNS in adult and during ontogenesis. These observations suggest that cytokines might be involved as regulating factors promoting CNS development.
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PMID:Developmental expression of cytokine genes in the cortex and hippocampus of the rat central nervous system. 780 81

In vitro immune responses to Legionella pneumophila were investigated. When human peripheral blood lymphocytes (PBL) from healthy volunteers were stimulated with formalin-killed L. pneumophila for 7 days in vitro, strong proliferative responses were observed. The responding cells were shown to be a CD4 T cell subset. It was also found that the CD4 T cells secreted significant amounts of IFN-gamma into the PBL culture supernatant. The production of IFN-gamma and IL-4 by PBL was measured semiquantitatively by reverse transcriptase-assisted polymerase chain reaction (RT-PCR) methods. Formalin-killed or live L. pneumophila-stimulated PBL expressed the mRNA for IFN-gamma but not the mRNA for IL-4. The results suggest that the whole bacterium, as opposed to the supernatant, predominantly stimulates Th1 type helper T cells. The cloned T cells specific for L. pneumophila expressed the mRNA for IFN-gamma but not for IL-4. In contrast to formalin-killed or live L. pneumophila stimulation, when PBL were stimulated with the bacterial culture supernatant, the proliferating T cells produced the mRNA for IL-4 as well as for IFN-gamma. A significant correlation between the proliferative response to formalin-killed L. pneumophila and IFN-gamma release in culture was observed (r = 0.6932, P < 0.001) in PBL from 30 healthy volunteers. From these in vitro studies, it is suggested that the whole L. pneumophila bacterium and their soluble antigens stimulate T cells in a manner which results in a different pattern of cytokine production.
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PMID:Interferon-gamma (IFN-gamma) production by human T lymphocytes upon Legionella pneumophila stimulation in vitro. 781 13

The inflammatory cytokines IFN-gamma and TNF-alpha have been demonstrated in various autoimmune diseases, and are thought to participate in the induction and pathogenesis of disease. TFN-alpha is a cytopathic cytokine that is cytotoxic for oligodendrocytes in vitro and has been implicated in the pathology of multiple sclerosis and its animal model experimental allergic encephalomyelitis (EAE). We used reverse transcriptase (RT)-PCR to study the kinetics, cellular source, and regulation of cytokine gene expression in the central nervous system (CNS) of SJL/J mice with myelin basic protein-induced EAE at different stages of the disease. The expression of CD3, IL-2, IFN-gamma, and TNF-alpha mRNA was barely detectable in the CNS of unmanipulated mice or mice that were immunized with adjuvant but showed no symptoms. These mRNAs were readily detectable in the CNS of mice during peak disease, then coordinately dropped to background levels during remission. Analysis of cells isolated from the CNS of mice with acute EAE showed that the Th1 cytokines, IL-2 and IFN-gamma, were produced by infiltrating CD4+ T cells. In contrast, TNF-alpha was predominantly transcribed by non-T mononuclear CNS cells, the majority of which were identified as microglia and macrophages by their Mac-1 phenotype. Microglia could be discriminated by their low expression of CD45. Incubation of freshly derived, adult microglia from normal, uninfiltrated, CNS with activated Th1 supernatant induced the production of TNF-alpha mRNA. Therefore, TNF-alpha is made by both CNS-resident microglia and infiltrating macrophages during EAE, and this production is tightly controlled by cytokines secreted by infiltrating CD4+ T cells.
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PMID:TNF-alpha expression by resident microglia and infiltrating leukocytes in the central nervous system of mice with experimental allergic encephalomyelitis. Regulation by Th1 cytokines. 781 94

Interleukin-3 (IL-3), a cytokine known to be produced by activated T lymphocytes, mast cells, eosinophils and neutrophils, is a potent stimulator of normal haemopoiesis, particularly megakaryocytopoiesis. However, it remains unknown whether leukaemic megakaryoblasts can produce IL-3 and whether IL-3 is involved in the pathological process of megakaryoblastic leukaemia. In this study, several human leukaemia cell lines with or without megakaryocytic features, the DAMI, MEG-01, HEL, K562, HL-60 and U937, were chosen as the models. It was first demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) and indirect immunofluorescence assay that IL-3 was expressed in DAMI and MEG-01 cells, but not in other cell lines, although two erythroleukaemic cells, the HEL and K562, also possess some megakaryocytic features. Interestingly, the mRNA for IL-3 receptor was detected in nearly all the cell lines except K562 cells, suggesting that expression of IL-3 and its receptor may be dissociated in most of the cell lines and that co-expression of IL-3 and its receptor exists in megakaryoblastic cell lines, the DAMI and MEG-01. Of the cell lines which did not express IL-3 under unstimulated condition, only HEL cells were able to express IL-3 mRNA after treatment with PMA for 72 h. Furthermore, the proliferation of DAMI and MEG-01 cells could be enhanced in the presence of IL-3 and suppressed by the anti-IL-3 antibody and the IL-3 antisense oligodexyonucleotides (ODNs). These findings indicate that IL-3, as an autocrine growth factor, is involved in the growth of some megakaryocytic leukaemia cell lines.
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PMID:Interleukin-3 is an autocrine growth factor of human megakaryoblasts, the DAMI and MEG-01 cells. 781 61

The effects of cytokine stimulation [recombinant human interleukin (rhIL)-1 alpha, rhIL-3, rhIL-6, rhIL-11, and rh granulocyte-macrophage colony-stimulating factor (GM-CSF)] on the secretory activity of normal human megakaryocytes were studied by means of the reverse hemolytic plaque assay (RHPA) in enriched cell preparations. This test facilitates an extremely sensitive determination of cytokine secretion at the single-cell level, together with the clear-cut identification of each immunostained (CD61) secretory active megakaryocyte. Moreover, the reverse transcriptase-polymerase chain reaction (RT-PCR) was used to investigate the expression of IL-6, IL-6 receptor (IL-6R), IL-9, IL-10, IL-12, and IL-13 mRNA in highly concentrated megakaryocyte preparations. In comparison with the spontaneous secretion rate, stimulation with rhIL-1 alpha, rhIL-6, and rhGM-CSF failed to induce a significant increase in the release of cytokines by CD61+ cells. On the other hand, both rhIL-3 and, in a less pronounced way, rhIL-11 exerted a marked effect on IL-6 secretion. Additionally, after stimulation with rhIL-3, a significant enhancement of the secretion of IL-3 and GM-CSF, but not of IL-1 alpha, could be observed. Using the RT-PCR, a significant induction of IL-6 expression could be appreciated in the enriched megakaryocyte population (60% to 80%) stimulated with rhIL-3. The results of this study provide persuasive evidence that a number of cytokines are synthesized and secreted by human megakaryocytes and not only by hematopoietic stroma cells. These data suggest the existence of autocrine and paracrine mechanisms that may influence maturation and differentiation of megakaryocytes as well as act on various stroma cells to sustain an appropriate hematopoietic micro-environment.
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PMID:Secretion of cytokines (interleukins-1 alpha, -3, and -6 and granulocyte-macrophage colony-stimulating factor) by normal human bone marrow megakaryocytes. 783 72

The expression of the cytokine genes in normal placenta was studied using RT-PCR method capable of detecting low levels of mRNA. Total RNA was prepared from placenta of specific pathogen-free BALB/c mice at the 16th day of gestation by acid guanidinium thiocyanate-phenol-chloroform (AGPC) method. cDNA was synthesized by M-MLV reverse transcriptase, and amplified using the specific oligonucleotide primers for IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, TNF-alpha, IFN-alpha, IFN-beta and IFN-gamma by PCR method. IL-1 beta, IL-6, TNF-alpha, IFN-alpha, IFN-beta and IFN-gamma mRNA were detected in all the placentas tested. On the other hand, the expressions of IL-2, IL-3, IL-4, and IL-5 mRNA were not detected at all. These results suggest that these cytokines may play a role in the evolution of pregnancy.
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PMID:[Expression of cytokine messenger RNA in murine placenta]. 783 98

The expression of the cytokine genes in human spleen was studied using reverse transcriptase-polymerase chain reaction (RT-PCR) method capable of detecting low levels of mRNA. Total RNA was prepared from human spleen by acid guanidinium thiocyanate-phenol-chloroform (AGPC) method. cDNA was synthesized by M-MLV RTase using oligo (dT)16 primer, and amplified using the oligonucleotide primers specific for IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, TNF-alpha, IFN-alpha, IFN-beta and IFN-gamma by PCR method. Although IL-1 beta, IL-4, IL-5, IL-6, IL-7, IL-8, TNF-alpha, IFN-alpha and IFN-gamma mRNA were detected in all the samples tested, IL-3 and IFN-beta mRNA was not detected at all. These results suggest that many kinds of cytokines may be produced constitutionally in human spleen, and its pattern of cytokine production was similar to that in mice.
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PMID:[Expression of cytokine messenger RNA in human spleen]. 783 9

Interleukin 10 (IL-10) was initially discovered on the basis of its ability to suppress cytokine synthesis. Additionally, it can exert immunosuppressive effects on a variety of cell types. Because patients with malignant gliomas present with a general impairment of the immune system, we investigated IL-10 expression in the glioma tissue. Because expression of IL-10 and IL-6 is associated in hematopoietic cells and IL-6 can act as an autocrine growth stimulator for glioblastoma cell lines, we looked in addition for a relationship between IL-10 and IL-6 expression. Using a quantitative reverse transcriptase polymerase chain reaction, IL-10 and IL-6 mRNA levels were determined in 37 glial tumors of different grades including 2 recurrencies, 3 specimens from normal brain tissue, and 3 glioblastoma cell lines. Expression of IL-10 mRNA was demonstrable in all tumors as well as in normal brain. High grade tumors and recurrent cases expressed significantly higher amounts of IL-10-specific mRNA compared with low grade tumors, whereas 2 of 3 cell lines showed only weak constitutive expression, mRNA for IL-6 was found in 86.5% of all gliomas with a correlation concerning the expression levels for both cytokines in 69% of gliomas. We suggest that IL-10 may contribute to the progression of astrocytomas by suppressing the patient's immune response, whereas IL-6 provides an additional growth advantage.
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PMID:Messenger RNA expression of the immunosuppressive cytokine IL-10 in human gliomas. 785 43


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