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)

The aim of the present study was to investigate the patterns of cytokine production by T cell clones raised from in vivo activated synovial fluid (SF) mononuclear cells (MNC) of five patients with oligoarticular juvenile arthritis (JA). Freshly isolated SF T cells were cultured in vitro with low dose recombinant IL-2 and subsequently cloned by limiting dilution. Sixty-four clones were obtained from the five patients studied. Fifty-nine clones were TCR alpha/beta+, either CD4+ (n = 43) or CD8+ (n = 15). The remaining five clones were TCR gamma/delta+, CD4-, CD8-. Clone immunophenotypes differed in the individual patients. Forty-four T cell clones were stimulated with phytohaemagglutinin (PHA) and phorbol myristate acetate (PMA) and supernatants tested for the presence of IL-2, IL-4, IL-5 and interferon-gamma (IFN-gamma) by ELISA or bioassays. Cytokine mRNA accumulation was tested by reverse transcriptase-polymerase chain reaction (RT-PCR). Most of 44 clones tested released large amounts of IFN-gamma irrespective of the immunophenotype. Of these, 27 were classified as Th1-type and 17 as Th0-type based upon the IFN-gamma/IL-4 ratio in culture supernatants. Finally, when 10 representative T cell clones were tested for pro- and anti-inflammatory cytokines, gene expression by RT-PCR, all of them were found to express the granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor-alpha (TNF-alpha), IL-10 and transforming growth factor-beta 1 (TGF-beta1) genes, and half of them IL-6 and IL-8 mRNA. In conclusion, T cell clones, that represent the progeny of in vivo activated SF T cells from oligoarticular JA patients, display heterogeneous immunophenotypes, but all share the ability to produce large amounts of IFN-gamma, with a predominant Th1/Th0 pattern. The expression of pro- and anti-inflammatory cytokine genes in these clones suggests that in vivo activated SF T cells modulate joint inflammation in a complex fashion.
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PMID:Synovial fluid T cell clones from oligoarticular juvenile arthritis patients display a prevalent Th1/Th0-type pattern of cytokine secretion irrespective of immunophenotype. 921 17

Chemokines are small proteins that selectively activate and recruit leukocytes to sites of inflammation. Several of them, including the CC chemokines RANTES, MIP-1 alpha, MIP-1 beta, MCP-1, and the CXC chemokines IL-8, GRO-alpha, ENA-78 have been identified in rheumatoid synovium, implicating a potential role for these molecules in rheumatoid arthritis. We have investigated the expression patterns of CC chemokine receptors in the joints of mice with collagen-induced arthritis, a model for human rheumatoid arthritis. In addition, we have investigated the incidence and severity of arthritis in mice receiving administration of MetRANTES, a modified chemokine which is a nanomolar antagonist of certain CC chemokine receptors. The mRNA expression pattern of the chemokines and their receptors in the joints of arthritic mice was investigated using reverse transcriptase-PCR and in situ hybridization. An upregulation of the CC chemokine receptors mCCR1, mCCR2; mCCR3 and mCCR5 was found in the joints from arthritic mice, compared to control animals. In addition, injections of MetRANTES reduced the incidence of disease in a dose dependent manner. Furthermore, in MetRANTES-treated mice that did develop arthritis a significantly lower severity of disease was observed compared with control animals. Our data clearly demonstrate a role for CC chemokines and their receptors in inflammatory joint destruction and support the use of chemokine receptor antagonists as potential tools to control inflammatory diseases such as rheumatoid arthritis.
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PMID:Effect of a CC chemokine receptor antagonist on collagen induced arthritis in DBA/1 mice. 923 36

Pro-opiomelanocortin (POMC)-derived peptides such as alpha-melanocyte-stimulating hormone (alpha-MSH) recently have been recognized as mediators with potent immunomodulating and anti-inflammatory properties. Their effects are mediated via different protein G-coupled melanocortin (MC) receptors that are capable to bind one or more POMC-derived peptides. Among these receptors, MC-1 is specific for alpha-MSH and adrenocorticotropin. The purpose of the present study was to investigate whether MC receptors are expressed on normal human dermal microvascular endothelial cells (HDMEC) as well as transformed human dermal microvascular endothelial cells (HMEC-1). Using semiquantitative reverse transcriptase-PCR and MC receptor-specific primers, both HDMEC and HMEC-1 were found to express MC-1 constitutively. In addition, MC-1 expression was increased upon stimulation with IL-1beta or alpha-MSH itself. Other known MC receptors were neither detectable in unstimulated nor in IL-1beta- or alpha-MSH-stimulated cells. The binding of alpha-MSH by HMEC-1 was specific and saturable as demonstrated by competitive and saturation-binding studies with 125I-labeled alpha-MSH (Kd: 1.1 nM). To evaluate the physiologic relevance of MC-1 expression, HMEC-1 were treated with various concentrations of alpha-MSH (10(-15)-10(-6) M) and were investigated for their cytokine-producing capacity. Alpha-MSH (10(-10)-10(-8) M) significantly up-regulated IL-8 release and mRNA expression by HMEC-1. In contrast, the production of IL-1 or IL-6 by HMEC-1 was not affected upon treatment with alpha-MSH. These data provide first evidence that HDMEC express functional MC receptors. Therefore, alpha-MSH, which is released in the skin during cutaneous inflammation via inducing chemokines may represent an important signal required for leukocyte-endothelial cell interaction.
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PMID:Human dermal microvascular endothelial cells express the melanocortin receptor type 1 and produce increased levels of IL-8 upon stimulation with alpha-melanocyte-stimulating hormone. 925 58

Active Helicobacter pylori-associated gastritis is characterized by a dense mucosal infiltration with granulocytes. Since H. pylori is noninvasive, secondary signals must induce the accumulation of granulocytes. Interleukin-8 (IL-8) has been shown to play a key role in this event. Using competitive reverse transcriptase-PCR on mRNA from gastric biopsies, we could show a clear correlation between the amount of IL-8 transcripts and the activity of H. pylori gastritis. Due to the inability of the bacterium to invade host cells, the epithelial layer is a potential candidate as an IL-8 source. To study the mechanism of IL-8 induction, established gastric carcinoma epithelial cell lines (AGS and Kato III) and well-defined H. pylori strains were used in a modified in vitro system. The experimental design enabled us to prevent direct contact of bacteria with epithelial cells by use of a filter membrane which did not block secreted bacterial products crossing the membrane. The data clearly showed that the direct contact of the bacterial cell with the epithelial cell is necessary for optimal IL-8 production because not only live bacteria, but also metabolically inactive bacteria, increased IL-8 secretion. Neither purified lipopolysaccharide nor water-soluble protein fractions of H. pylori NCTC 11637 and Tx30a nor the cytotoxin of H. pylori was able to increase IL-8 production significantly by the epithelial cells used. Furthermore, preparations of total membrane and outer membrane proteins of H. pylori were not able to stimulate IL-8 release in vitro. Accumulatively, these results imply that active metabolism is not necessary for stimulation as long as there is an intact membrane aiding the presentation of a stimulating membrane complex or aggregate on the surface of the bacteria. From these results, we conclude that whole bacteria and their direct contact with epithelial cells may be critical for IL-8 induction in vivo.
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PMID:Role of adherence in interleukin-8 induction in Helicobacter pylori-associated gastritis. 928 28

The presence of mRNA transcripts for cytokines in normal and neoplastic human breast tissue has been investigated. Using reverse transcriptase-linked polymerase chain reaction (RT-PCR), we have specifically screened for the following cytokines: interleukin (IL)-1alpha, IL-1beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, tumour necrosis factor (TNF)-alpha, TNF-beta and interferon (IFN)-gamma. No significant differences in expression of IL-1alpha, IL-1beta, IL-4, IL-6, TNF-alpha or TNF-beta were observed between the 2 groups of tissues. However, there was a significant difference in expression of IL-8 transcripts (p = 0.0017) which was higher in the neoplastic population. Transcripts for IL-2, IL-3, IL-5, IL-7 and IFN-gamma were not detected in either group. There was no evidence of associations between cytokine expression and tumour histological grade, patient age or lymph node metastases. Correlating tumour types with specific cytokine transcripts revealed high expression of IL-8, and to a lesser extent, IL-8 and TNF-beta irrespective of tumour origin. Analysis of primary epithelial and stromal cultures derived from both types of tissue showed that increased levels of IL-8, but not IL-6, were secreted by cells obtained from tumours. Thus, breast tissue of both normal and neoplastic origin expresses a wide range of cytokines. Increased or aberrant expression of cytokines, in particular IL-8, may be involved in the development/progression of breast cancer.
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PMID:Expression of cytokine messenger RNA in normal and neoplastic human breast tissue: identification of interleukin-8 as a potential regulatory factor in breast tumours. 937 54

Neutrophils in the cerebrospinal fluid (CSF) increase during the initial stage of meningitis. Some cytokines induce the accumulation of such neutrophils, and we and other investigators have revealed transient increases in the levels of granulocyte-colony stimulating factor (G-csf) and IL-8 in the CSF of patients with meningitis. To explore the coordination of other cytokines with G-csf and IL-8 in the neutrophil accumulation in the CSF, we herein investigated macrophage inflammatory protein-1alpha (MIP-1alpha), which can induce the infiltration of neutrophils. The modulation of MIP-1alpha levels in the CSF in children with bacterial (n = 10) and aseptic (n = 22) meningitis was examined using an ELISA. MIP-1alpha levels in the CSF were detectable at the stage with symptoms of meningitis: 289.9 +/- 270.7 ng/L in the bacterial meningitis group and 16.1 +/- 12.5 ng/L in the aseptic meningitis group. These levels decreased with the improvement of symptoms. MIP-1alpha was not detectable (<6 ng/L) in all of the control patients without meningitis (n = 19). The MIP-1alpha levels in the CSF showed a significant correlation with the CSF neutrophil counts (r = 0.750, p < 0.0001; n = 80) of meningitis, and the values of MIP-1alpha (log ng/L)/neutrophil counts (log/L) ratio were calculated (1.003 +/- 0.576). The MIP-1alpha levels in the serum were significantly lower than those in the CSF (p = 0.0464). We found MIP-1alpha mRNA in the CSF cells by the reverse transcriptase-PCR method, and high levels of MIP-1alpha protein in the culture media from mononuclear cells in the CSF in vitro. In summary, The MIP-1alpha level increases in the CSF at the symptomatic stage of meningitis in children, and its cellular source is, in part, mononuclear cells which have infiltrated the CSF. We propose that MIP-1alpha, in addition to G-csf and IL-8, plays an important role in the accumulation of neutrophils in the CSF of patients with meningitis.
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PMID:The production of macrophage inflammatory protein-1alpha in the cerebrospinal fluid at the initial stage of meningitis in children. 939 59

In contrast to a mutant adhesin-deficient Streptococcus pyogenes (group A streptococcus), its isogenic parental strain binds to human keratinocytes and promotes a vigorous proinflammatory response, characterized by enhanced expression of several cytokines, a more rapid release of prostaglandin E2 (PGE2) and damage to keratinocyte membranes. However, adherence alone is not sufficient to induce these responses. In this study, we have begun to examine the contribution of other streptococcal products in interactions with keratinocytes by the construction and evaluation of mutants deficient in expression of the secreted pore-forming haemolysin, streptolysin O (SLO). Inactivation of SLO did not prevent the streptococci from adhering to cultured HaCaT keratinocytes or from expressing an unrelated second streptococcal haemolysin, streptolysin S, during infection of keratinocytes. As measured by a quantitative reverse transcriptase polymerase chain reaction (PCR) assay, inactivation of SLO also did not have a marked effect on the expression of interleukin 1alpha (IL-1alpha) during infection. However, the lack of the ability to produce SLO was associated with a considerable reduction in expression of IL-1beta, IL-6 and IL-8 by infected keratinocytes. Measurement of the release of PGE2 by an enzyme-linked immunosorbent assay demonstrated that the SLO-deficient mutants were also not capable of promoting the rapid high level of PGE2 release characteristic of the adherent SLO-producing parental strain. Finally, analyses using the fluorescent probe ethidium homodimer-1 and measurements of release of keratinocyte lactate dehydrogenase indicated that the failure of the SLO-deficient mutants to induce responses was associated with the failure of these mutants to damage the integrity of the keratinocyte membrane. These data implicate SLO as a factor that acts synergistically with an adhesin to modulate the signalling responses of keratinocytes during infection.
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PMID:Streptolysin O and adherence synergistically modulate proinflammatory responses of keratinocytes to group A streptococci. 948 89

Cytokines are signalling glycoproteins mediating acute inflammation, chronic inflammation, and connective tissue destruction. The present study was designed to characterize the profile of cytokine message in normal human articular cartilage and from patients with rheumatoid arthritis (RA) and osteoarthritis (OA), by means of the reverse transcriptase-polymerase chain reaction (RT-PCR). Message RNA (mRNA) was extracted from fresh or frozen cartilage. The results showed expression of mRNA for IL-6, IL-6R, IL-7, IL-8, IL-10, and IL-12 (p35 and p40) exclusively in the RA cartilage. Except for mRNA for IL-8 and IL-10, no other cytokine or cytokine receptor was expressed in OA and control cartilage. mRNA for IL-1beta, IL-4, TNF-alpha, and TNFR-p75, was not detected in any cartilage sample except for one RA specimen expressing IL-1beta mRNA. However, the expression of message for pro-inflammatory cytokines was far more prominent than anti-inflammatory cytokines. This may suggest a disturbed balance of pro- and anti-inflammatory activity in RA cartilage.
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PMID:Detection of cytokine mRNA in human, articular cartilage from patients with rheumatoid arthritis and osteoarthritis by reverse transcriptase-polymerase chain reaction. 950 80

Cytokines appear to play an important role in the development and progression of epithelial tumors. Cultured normal human thyroid follicular cells constitutively release high levels of interleukin-6 (IL-6) and IL-8, together with low to moderate levels of transforming growth factor-alpha (TGF-alpha) and TGF-beta. IL-6 appears to play multiple functions in thyroid physiology and disease. Because certain data indicate an inverse relationship between IL-6 production and epithelial tumor aggressiveness, we used both tissue culture methods and histochemical techniques to search for possible alterations of cytokine expression in thyroid carcinomas. As compared to cultures from normal tissue and well-differentiated carcinoma, production of IL-6 was strongly down-regulated in cultures derived from undifferentiated carcinoma. In contrast, levels of IL-8, TGF-alpha, and TGF-beta produced by neoplastic TFC were similar to those produced by normal cells. Actually, production of TGF-alpha was slightly enhanced in cultures from well-differentiated carcinoma. Immunoassay results were confirmed by reverse transcriptase-PCR analysis. Immunohistochemistry of human thyroid carcinomas (n = 99) and normal thyroid tissue (n = 85) showed that immunoreactive IL-6 was strongly diminished in undifferentiated forms (n = 34) and slightly reduced in well-differentiated carcinoma (n = 65). In agreement with the in vitro results, TGF-alpha expression was significantly increased in neoplastic thyrocytes, as compared to their normal counterpart. The results indicate that, as in the mammary and salivary glands, down-regulation of IL-6 expression may represent a marker of undifferentiated thyroid carcinoma.
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PMID:Reduced expression of interleukin 6 in undifferentiated thyroid carcinoma: in vitro and in vivo studies. 951 26

High concentrations of oxygen, indispensable for the treatment of severe hypoxemia from neonatal as well as adult respiratory distress syndrome, increase the risk of oxygen toxicity. Biochemical mechanisms are lipid peroxidation, protein sulfhydryl oxidation, enzyme inactivation, and DNA damage. Recent reports suggest that cytokines might be involved in free radical injury as well as in adaptive response to hyperoxic injury. However, actual signal transduction pathways involving cytokines have not yet been clarified. In this study we exposed cultured human umbilical vein endothelial cells (HUVECs) to either ambient air or 100% oxygen, and compared for the rate of DNA synthesis ([3H]thymidine uptake) at different time points up to 72 h. After exposing the cells to each treatment condition, we extracted RNA, constructed complementary DNA using reverse transcriptase, amplified the specific DNA segments of cytokines by polymerase chain reaction (PCR), and used the PCR products for gel electrophoresis to examine the bands which signified mRNA levels of corresponding cytokines. There was a significant decrease in the rate of DNA synthesis as early as 24 h. The mRNA expression of IL-1 beta and TNFa seemed less influenced by hyperoxia, while IL-8 and TGF beta showed marked increase in mRNA levels at 6 h of 100% oxygen exposure.
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PMID:Hyperoxia influences mRNA expression of cytokines in cultured human umbilical vein endothelial cells. 952 79


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