Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protein phosphorylation is considered an early cellular mechanism of signal transduction by surface immunoglobulins (sIg) and other receptors of B cells. Using intact human peripheral blood B cells of young subjects labeled with orthophosphate, increased phosphorylation levels of serine/threonine and tyrosine substrates were demonstrated on indicator phosphoproteins corresponding to the CD20 isoforms and microtubule-associated protein 2 kinase after cross-linking sIg and costimulation with phorbol diesters. By contrast, stimulated B cells from certain elderly subjects displayed substantial alterations in the phosphorylation patterns of serine/threonine or tyrosine indicator phosphoproteins. Also, age-related impairments in sIg stimulated mobilization of cytosolic protein kinase C (PKC) enzymatic activity and in cytosolic calcium [Ca2+]i responses of B cells were observed with the altered phosphorylation reactions. Comparison of the substrate phosphorylation profiles to the proliferative responses of stimulated B cells from individual elderly subjects suggested a model of signal transduction in which differing stimuli have different dependencies on phosphorylation reactions. Diminished proliferative responses after sIg ligation coincided with decreased phosphorylations of either tyrosine or serine/threonine indicator substrates. However, the decreased proliferative responses of B cells from elderly subjects with substantial reductions of tyrosine phosphorylation after sIg ligation were enhanced by the direct stimulation of serine/threonine kinase activity with phorbol diesters or CD40 ligation. Experiments with kinase inhibitors evaluated the relative dependency of different B cell stimuli on tyrosine and serine/threonine phosphorylation reactions. The proliferative responses of normal B cells to sIg ligation were quite sensitive to the tyrosine kinase inhibitor genistein whereas those observed following costimulations with phorbol diesters or CD40 ligation were more resistant. However, treatment of B cells with H7, an inhibitor of PKC activity, led to a more uniform reduction of B-cell responses after different stimuli. Results from RNase protection assays of c-myc expression also suggested that different B-cell stimuli might utilize distinct intracellular signaling pathways. Both the type of stimuli and mode of sIg ligation were important in determining the stimulated levels of c-myc mRNA expression. Thus, the current findings suggest that age-related defects are present in human B cell signaling pathways as reflected by tyrosine and serine/threonine phosphorylation reactions. Also, these age-related defects can coexist with altered mobilization of PKC enzymatic activity and with alterations in [Ca2+]i and proliferative responses.
Lymphokine Cytokine Res 1991 Dec
PMID:Signal transduction in human B cells during aging: alterations in stimulus-induced phosphorylations of tyrosine and serine/threonine substrates and in cytosolic calcium responsiveness. 180 9

In order to examine the regulation of cytokine receptor gene expression an RNase protection assay (RPA) was developed that allows the simultaneous and semiquantitative measurement of mRNAs encoding for the IL-1 p60 and p80, TNF p55 and p75, IFN-gamma, and IL-6 receptors. Titration experiments revealed that this method was very sensitive allowing the detection of the target cytokine receptor mRNAs down to at least 0.01 microgram of spleen poly(A)+ RNA. The cytokine receptor RPA was used to examine the expression of the receptor genes in various organs from normal mice and mice that had been injected with LPS. In normal mice expression of the IL-1R p80, TNFR p55 and p75, IFN-gamma, and IL-6R but not the IL-1R p60 transcripts was readily detectable in spleen, liver, kidney, and brain. Following LPS treatment, there was an induction of the IL-1R p60 mRNA in all organs and an up-regulation of the IL-1R p80, TNFR p55 and p75, IFN-gamma, and IL-6 receptor mRNAs particularly in spleen, liver, and kidney. Interorgan differences were observed in the regulation of these receptor mRNAs, indicating an organ-specific response to the LPS challenge. Our findings indicate the cytokine receptor RPA is a powerful and versatile tool for the simultaneous analysis of multiple cytokine receptor mRNAs in tissue samples. This technique will prove valuable in further evaluating the coordinated regulation of the expression of these genes, which are pivotal in the biology of cytokines.(ABSTRACT TRUNCATED AT 250 WORDS)
Lymphokine Cytokine Res 1994 Apr
PMID:Simultaneous analysis of multiple cytokine receptor mRNAs by RNase protection assay in LPS-induced endotoxemia. 806 Nov 11

In this study, we have analyzed the expression and regulation of receptors for IL-2 (alpha and beta chains) and IL-4 in four lymphoid cell lines established from leukemic cells. The gibbon ape cell line MLA 144 was the only one to express constitutively the IL-2R beta chain and IL-4R, whereas the NK-like YT cells express only IL-2R beta. The two other cell lines in this study, PEER and HSB2, are derived from T lymphocytes, and express neither IL-4R, IL-2R beta, nor IL-2R alpha unless stimulated. We report here that those receptors that are constitutively expressed, i.e., IL-2R beta on YT cells and IL-2R beta or IL-4R on MLA cells, are down-regulated by stimulation with PHA + PMA. In contrast, RNase protection experiments showed that PHA + PMA stimulation of T cell lines induces mRNA for all three receptors in PEER cells, and only IL-2R alpha and IL-4R in HSB-2. Thus each of these three receptors is subjected to a different regulation, which in addition varies depending on the lineage (or differentiation stage) of the cells. This was further supported by the finding that IL-1 alpha or TNF-alpha regulates these receptors differently. These two cytokines have no effect on IL-2R beta and IL-4R in MLA and YT, but induce IL-2R alpha in YT. In contrast, they do not induce either chains of the IL-2R in the T cell lines PEER or HSB-2, but TNF induces IL-4R mRNA in HSB2 cells, and IL-1 does so in both cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)
Lymphokine Cytokine Res 1993 Feb
PMID:Regulation of interleukin-2 and interleukin-4 receptor expression in human and ape lymphoid cell lines. 845 29

We have identified a new antiproliferative activity from the conditioned medium of two androgen-independent prostatic cancer cell lines, PC3 and DU-145. This antiproliferative activity selectively inhibited cell proliferation of an androgen-dependent prostate cancer cell line LNCaP in a dose-dependent manner. No antiproliferative activity was observed against mouse fibroblast 3T3, normal human lymphocytes, human leukemic cells, including promyelocyte HL-60 or T cell HUT-78, or human adenocarcinoma cell lines, including prostatic cells JCA-1, ovary NIH:OVCAR-3, cervix C-33A, or breast MDA-MB-231. Cell cycle analysis revealed that the antiproliferative activity did not induce apoptosis in LNCaP cells, but it prevented some G1 LNCaP cells from entering into the S phase of the cell cycle. The antiproliferative activity was sensitive to high temperature (100 degrees C) and to proteinase digestion; however, it was resistant to 56 degrees C, pH 2.0, and reducing agent treatment, as well as to DNase and RNase digestion. The antiproliferative activity was partially purified by gel filtration, ion-exchange chromatography, and SDS-PAGE, with an apparent molecular weight of 50 kD. The antiproliferative activity was not affected by neutralizing antibody against TGF-beta 1,2,3, TNF-alpha, PDGF, EGF, IL-1, IL-2, IL-3, IL-4, or IL-6.
J Interferon Cytokine Res 1995 Feb
PMID:Antiproliferative effect of a prostatic cell-derived activity on the human androgen-dependent prostatic carcinoma cell line LNCaP. 859 Mar 22

Predesquamin is a glycoprotein found in the transition layer and the lower stratum corneum of human epidermis. Interferon-gamma (IFN-gamma) induces the synthesis of predesquamin by keratinocytes in culture. We now show ultrastructurally that exogenous addition of either predesquamin or IFN-gamma to cultured keratinocytes induces apoptotic nuclei with condensed chromatin. Degradation of cellular DNA is also evident as a ladder pattern in an agarose gel. After incubation with both predesquamin and IFN-gamma (but not either alone), the mobility of plasmid DNA in a gel shows retardation specific for guanine residues. This binding to the DNA may impart to it a conformational change that facilitates access by endogenous cellular nucleases. In epidermal cells cultured with IFN-gamma supplementation, we also show by RT-PCR that there is an upregulation of the genes c-myc, p53, gadd45, dsRNA-activated protein kinase, and 2'-5'-oligo(A)-dependent RNase, which have all been implicated in apoptosis in other cell types. These results are pertinent to the mechanism of occurrence of apoptosis in the epidermis in vivo, where predesquamin and IFN-gamma are endogenous. Programmed cell death is an inherent step in the terminal differentiation and desquamation of the epidermis.
J Interferon Cytokine Res 1995 Dec
PMID:Induction of apoptotic nuclei by interferon-gamma and by predesquamin in cultured keratinocytes. 874 83

Myofibroblasts have been previously described beneath the bronchial epithelium and were found to increase in number proportional to the accumulation of extracellular matrix in the bronchial lamina reticularis in asthma. The aim of this study was to assess further the contribution of these structural cells to allergic inflammation in the bronchial mucosa through their cytokine expression. Cell cultures were established from the lamina reticularis of human bronchial biopsies from asthmatic and non-asthmatic subjects. Cytokine secretion was measured by ELISA in supernatants of cultures with or without tumour necrosis factor-alpha (TNF-alpha). The mRNA levels for granulocyte-macrophage colony-stimulating factor (GM-CSF) in the cultures were examined by ribonuclease protection assays (RPAs). Bronchial myofibroblasts grown from bronchial biopsies were capable of producing GM-CSF, interleukin-6 (IL-6), interleukin-8 (IL-8), and stem cell factor (SCF) constitutively. The GM-CSF production by myofibroblasts was significantly increased in response to TNF-alpha simulation with a corresponding increase in GM-CSF mRNA expression. The enhancement of GM-CSF production by TNF-alpha in myofibroblasts was blocked by the inhibition of RNA synthesis. Prednisolone abolished the GM-CSF production. This study provides evidence for the role of bronchial myofibroblasts in the regulation of inflammatory cell recruitment and activation by interaction in the cytokine network in the bronchial mucosa.
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PMID:Cytokine production by cell cultures from bronchial subepithelial myofibroblasts. 894 23

Activation of T cells in the intestinal mucosa in response to gluten exposure is thought to play a key role in the pathogenesis of coeliac disease. Moreover, the response of the rectal mucosa to gluten challenge has been considered a useful predictor of gluten sensitivity in coeliac disease. In the present study, we assessed early changes in the expression of proinflammatory cytokine genes and the T cell receptor (TCR) Vbeta repertoire in the rectal mucosa of coeliac disease patients following experimental gluten challenge. Cytokine gene expression was assessed in rectal mucosal biopsies from coeliac disease subjects and controls before and after rectal gluten challenge using quantitative reverse transcription polymerase chain reaction analysis, and the TCR Vbeta repertoire was characterized using a multiprobe RNase protection assay. Marked up-regulation of expression of the C-X-C chemokine IL-8, the proinflammatory cytokine IL-1beta, and the C-C chemokine monocyte chemotactic protein-1 occurred within 24 h of rectal gluten challenge in coeliac disease subjects, but not in controls. Furthermore, these changes occurred in the absence of parallel changes in the expressed repertoire of TCR Vbeta genes in the rectal mucosa. Thus, an increased expression of proinflammatory cytokine genes precedes the expansion of antigen-specific T cell populations in the early period following experimental exposure of the rectal mucosa of coeliac disease patients to gluten. These findings provide new insights into pathways that may be involved in the activation or reactivation of coeliac disease.
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PMID:Increased proinflammatory cytokine gene expression in the colonic mucosa of coeliac disease patients in the early period after gluten challenge. 901 Feb 69

RNase L (also termed 2-5A-dependent RNase) is a crucial enzyme involved in the molecular mechanism of interferon (IFN) action. Activated by 2',5'-oligoadenylate oligomers (2-5A), this enzyme controls the regulation of RNA stability in IFN-treated or virus-infected mammalian cells. Knowledge of RNase location within cells may provide additional information about its function. Previous work located RNase as a detergent-soluble molecule in nuclei and cytoplasm. In this study, we demonstrate that this enzyme was also present in a detergent-insoluble fraction associated with proteins of the cytoskeleton. A cellular fractionation procedure was used to prepare the cytoskeleton, which was shown to contain 2-5A binding activity not due to cytoplasmic contaminants. In contrast to the cytoplasmic fraction, which contained RNase L with a 2-5A-accessible site, the insoluble RNase molecular form of the cytoskeleton could not be assayed by the classic radiobinding method or the covalent UV cross-linking procedure, which only detects the 2-5A binding site in an open position, that is, free of 2-5A or with an unmasked 2-5A site. The 2-5A binding site present in the cytoskeleton was completely masked and not directly accessible to its 2-5A activator. This particular molecular form of RNase can be detected after a specific denaturing-renaturing treatment of the cytoskeleton, which separates the RNase from cytoskeletal proteins, unmasking the 2-5A site. The cytoskeletal RNase was no longer present at this site when cells were stimulated for a short time with 12-O-tetradecanoylphorbol-13-acetate (TPA). Our data suggest the existence of a pathway that targets the RNase to another subcellular location. To explore the issue further, we examined in vitro the ability of calcium and phospholipid-dependent protein kinase C (PKC) to catalyze significant phosphorylation of the RNase.
J Interferon Cytokine Res 1998 Jun
PMID:Localization of a molecular form of interferon-regulated RNase L in the cytoskeleton. 966 Feb 42

Cytokine-driven activation of hepatic stellate cells (HSC) in tissue injury and inflammation is a key pathogenetic event in liver fibrogenesis leading to an expanded pool of matrix producing myofibroblasts (MFB) which represent the transformed counterpart of HSC. We hypothesize that expansion of the pool of MFB might also be accomplished by modulation of apoptosis, which plays an opposite and complementary role to mitosis in the cellular homeostasis. We characterized the susceptibility of HSC in primary culture and of MFB in secondary culture to apoptosis induced by the soluble Fas ligand (sFasL) and related the effects to the expression levels of Fas (APO-1/CD95) and some major proapoptotic and contra-apoptotic protooncogenes. MFB showed a dose-dependent apoptotic reaction upon exposure to sFasL as evidenced by a strong increase of nucleosomal DNA fragments, loss of cellular DNA, positive TUNEL reaction, and annexin staining. The effect was found only if protein synthesis (cycloheximide) or RNA synthesis (actinomycin D) were arrested. HSC maintained for various times in primary culture were completely resistant to sFasL in combination with cycloheximide, but in late primary cultures (day 7 onward) an increasing susceptibility to sFasL-mediated apoptosis was developed. By semiquantitative reverse-transcriptase polymerase chain reaction (RT-PCR) analysis and alkaline phosphatase-anti-alkaline phosphatase staining Fas receptor was identified both in HSC and MFB at comparable expression levels. The expression of the contra-apoptotic protooncogenes bcl-2 and bcl-xl was found to be much stronger in early HSC than in late HSC and MFB as shown by ribonuclease protection assay. The expression of bcl-2 was additionally confirmed by semiquantitative RT-PCR and immunoblotting. Proapoptotic bax was found in comparable quantities at the RNA level in HSC and MFB but at the protein level MFB showed increased bax expression. It is concluded that transformation of HSC to MFB is paralleled by an increasing sensitivity to sFasL-mediated apoptosis, which might be related to a strong decrease of bcl-2 and bcl-xl expression, leading to a preponderance of proapoptotic gene expression in MFB. Modulation of apoptotic susceptibility of transforming HSC could be an important complementary pathway in the pathogenesis of fibrosis.
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PMID:Transformation-dependent susceptibility of rat hepatic stellate cells to apoptosis induced by soluble Fas ligand. 969 16

Studies indicate that lymphoid tissue (e.g., thymus, bone marrow, and Peyer's patches) shows evidence of increase apoptosis (Ao, a form of nonnecrotic cell death) during sepsis. However, it is not known if mucosal lymphoid tissue, such as lamina propria (LP), also shows evidence of increased Ao and if so, is this associated with functional changes, i.e., cytokine gene expression in the LP. To examine this, male C3H/HeN mice were subjected to cecal ligation and puncture (CLP) and lamina propria mononuclear cells (LPMC) were harvested at 4 h (early sepsis) or 24 h (late sepsis). Alterations in the cell phenotype as well as Ao (Tunel assay) were determined by three-color flow cytometry. Cytokine gene expression was assessed by multiprobe RNase protection assay. Sham LPMC preparations were found to be 34.4 +/- 2.4% B220(+) (B-cells), while 12.4 +/- 2.1% were CD8(+) (cytotoxic T-cells), 22.0 +/- 0.8% were CD4(+) (helper T-cells), and 6.4 +/- 0.7% were F4/80(+) (macrophages). The frequency of B220(+) (9%* upward arrow) and CD8 (6%* upward arrow) populations increased markedly at 4 h after CLP; however, this increase was not seen at 24 h. The percentage of Ao+ in CD8(+), B220(+), and F4/80(+) cells increased markedly at both 4 and 24 h. CD4(+) cells showed a marked increase in Ao only at 24 h after CLP. When LPMC mRNA expression was examined, a significant increase in IL-2, -10, and -15 gene expression was observed only at 24 h but not 4 h after CLP. Thus, the early phenotypic changes associated with increased Ao may be a reflection of localized immune cell activation in early sepsis contributing to the increased cytokine gene expression seen in late sepsis. This localized activation may contribute to gastrointestinal inflammation and/or immune dysfunction in sepsis.
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PMID:Sepsis induces increased apoptosis in lamina propria mononuclear cells which is associated with altered cytokine gene expression. 969 35


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