Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have investigated the requirements for the induction of the acute phase response to inflammation using the FAZA rat hepatocyte cell line which can be induced to activate the acute phase response genes with supernatants from human or rat monocytes. Using ribonuclease mapping of fibrinogen transcripts, we find that the tumor promoter 12-O-tetradecanoylphorbol-13-acetate can induce a 10-20-fold increase in properly initiated and spliced fibrinogen mRNA. This response is likely to be mediated by protein kinase C (Ca2+/phospholipid-dependent enzyme) since the synthetic diacylglycerol, 1-oleoyl-2-acetylglycerol, can also induce fibrinogen mRNA. In addition to the alpha, beta, and gamma chains of fibrinogen, other acute phase response mRNAs are induced by 12-O-tetradecanoylphorbol-13-acetate including alpha 2-macroglobulin. The active agent capable of inducing the fibrinogen mRNAs in the monocyte supernatants is clearly not interleukin 1 (IL-1) or tumor necrosis factor. The FAZA cell line does not have detectable IL-1 receptors and does not respond to either murine or human IL-1 or the 30-kDa precursor for IL-1. In addition, fibrinogen cannot be induced by tumor necrosis factor alpha in this cell line, and the active agent in monocytes supernatants cannot be neutralized with polyclonal or monoclonal antibodies to tumor necrosis factor alpha. We conclude that a third as yet uncharacterized agent is responsible for the induction of fibrinogen during the acute phase response and that this agent transduces its signal to the fibrinogen genes by a mechanism involving protein kinase C.
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PMID:Induction of fibrinogen and a subset of acute phase response genes involves a novel monokine which is mimicked by phorbol esters. 244 Aug 78

Borna disease virus (BDV) causes central nervous system (CNS) disease in several vertebrate species, which is frequently accompanied by behavioral abnormalities. In the adult rat, intracerebral (i.c.) BDV infection leads to immunomediated meningoencephalitis. In contrast, i.c. infection of neonates causes a persistent infection in the absence of overt signs of brain inflammation. These rats (designated PTI-NB) display distinct behavioral and neurodevelopmental abnormalities. However, the molecular mechanisms for these virally induced CNS disturbances are unknown. Cytokines play an important role in CNS function, both under normal physiological and pathological conditions. Astrocytes and microglia are the primary resident cells of the central nervous system with the capacity to produce cytokines. Strong reactive astrocytosis is observed in the PTI-NB rat brain. We have used a ribonuclease protection assay to investigate the mRNA expression levels of proinflammatory cytokines in different brain regions of PTI-NB and control rats. We show here evidence of a chronic upregulation of proinflammatory cytokines interleukin-6, tumor necrosis factor alpha, interleukins-1alpha, and -1beta in the hippocampus and cerebellum of the PTI-NB rat brain. These brain regions exhibited only a very mild and transient immune infiltration. In contrast, in addition to reactive astrocytes, a strong and sustained microgliosis was observed in the PTI-NB rat brains. Our data suggest that CNS resident cells, namely astrocytes and microglia, are the major source of cytokine expression in the PTI-NB rat brain. The possible implications of these findings are discussed.
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PMID:Cytokine expression in the rat central nervous system following perinatal Borna disease virus infection. 1022 22

Cytokines induce apoptosis in pancreatic beta cells, but the exact mechanisms and sequence of events are not clear. Here, we investigate a role for tumor necrosis factor alpha (TNF-alpha) in the apoptosis of beta cells. Using the ribonuclease (RNase) protection assay and the reverse transcriptase-polymerase chain reaction (RT-PCR) method, we confirmed that TNF receptor 1 (TNFR1), TNFR1-associated death domain protein (TRADD), Fas receptor-associated intracellular protein with death domain (FADD), and FADD-like interleukin-1beta-converting enzyme (FLICE) were expressed in the pancreatic beta cell line, MIN6 cells. Fluorescent microscopic examination using Hoechst 33342 dye (Sigma, St Louis, MO) demonstrated that TNF-alpha induced time- and dose-dependent apoptotic nuclear changes in these beta cells. In situ end-labeling (ISEL) DNA analysis revealed that 10 nmol/L TNF-alpha generated new 3'-OH DNA strand breaks. Moreover, qualitative assessment of the induced DNA damage on agarose gels showed that 10 nmol/L TNF-alpha produced characteristic apoptotic patterns of DNA fragments formed by internucleosomal hydrolysis of static chromatin. In addition, C2-ceramides and natural ceramides dispersed in a solvent mixture of ethanol and dodecane induced characteristic features of apoptosis in MIN6 cells, mimicking TNF-induced DNA damage. We also determined endosomal ceramide production after TNF-alpha (10 nmol/L) treatment in MIN6 cells using the diacylglycerol kinase assay. These results suggest that TNF-alpha can cause apoptosis in pancreatic beta cells through TNFR1-linked apoptotic factors, TRADD, FADD, and FLICE, and TNF-induced ceramide production may be involved in the pathways.
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PMID:Tumor necrosis factor alpha signaling pathway and apoptosis in pancreatic beta cells. 1059 77

Fumonisin B(1) (FB(1)), a carcinogenic mycotoxin produced primarily by fungus Fusarium verticillioides in corn, causes several fatal animal diseases. In mice, liver is the primary site of its toxicity. Our previous study showed that maximum induction of interferon gamma (IFNgamma) and tumor necrosis factor alpha (TNFalpha) was observed at 4 and 8 h, respectively, after an acute po FB(1) treatment. To further investigate the time-related induction of other cytokines and genes involved in apoptosis signaling, male BALB/c mice were administered orally with either saline or 25 mg/kg of FB(1) and sampled 4 or 8 h after treatment. Expression of various genes was analyzed by ribonuclease protection assay. FB(1) treatment caused increased expression of TNFalpha and interleukin (IL)-1beta in both liver and kidney, whereas IL-1alpha and IL-1 receptor antagonist (IL-1Ra) expression was induced only in the liver. Expression of TNFalpha signaling molecules, TNF receptor 55 and receptor interacting protein, was increased in liver and kidney after FB(1) treatment. Caspase 8 expression was increased only in liver with no changes in kidney with FB(1). FB(1) treatment induced expression of Fas in liver and kidney with no alterations in Fas signaling molecules, Fas ligand, Fas-associated death domain and Fas-associated protein factor. Treatment of mice with FB(1) increased the expression of B-Myc, c-Myc and Max, oncogenic transcription factors in the kidney. FB(1) toxicity caused induction of cytokine network in liver with involvement of TNFalpha signaling pathway. Increased expression of caspase 8 involved in the TNFalpha signaling pathway may contribute to the apoptosis, whereas IL-1Ra induction could contribute to the proliferating effects observed in FB(1) toxicity.
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PMID:Fumonisin B(1)-induced alterations in cytokine expression and apoptosis signaling genes in mouse liver and kidney after an acute exposure. 1188 48

Previous studies suggest that tumor necrosis factor alpha (TNF-alpha) and the TNFRI (p55) and TNFRRII (p75) receptors mediate the pulmonary fibrotic response to silica. In order to further define the role of the TNFRI (p55) receptor in induction of profibrotic chemokines by low-dose silica/crystalline silica (50 micro g/50 micro l/mouse) or control diluent saline was instilled into the trachea of TNFRI gene ablated ((-/-)) and C57BL/6 (WT) control mice. Lung tissue was harvested and bronchoalveolar lavage (BAL) performed 24 h and 28 days following silica administration. Selected profibrotic chemokine mRNAs were quantified by ribonuclease protection assay, normalized to ribosomal protein L32 mRNA content and expressed relative to saline control treated lungs. Induction of MIP-1beta, MIP-1alpha, MIP-2, IP-10, and MCP-1 mRNAs was attenuated in the TNFRI(-/-) mice, in comparison to WT mice, particularly at 28 days after exposure. ELISA assays for MIP-1alpha and MIP-2 in homogenized lung tissue similarly demonstrated marked induction of both chemokines 24 h after silica treatment, which was persistent at 28 days in WT but not in TNFRI(-/-) mice. The percentage of BAL cells that was neutrophils was comparably increased in WT and RI(-/-) lungs at 24 h (49 +/- 12% vs. 46 +/- 10%) and 28 days (6.2 +/- 1.5% vs. 4.5 +/- 1%). The increase in total lavagable cells and BAL protein was also independent of strain. Histology revealed mild alveolitis without granuloma formation in both strains, slightly decreased in TNFRI(-/-). This study demonstrates an increase in pro-fibrotic chemokines in response to a single intratracheal exposure to crystalline silica that was sustained at 28 days after treatment in WT but not in TNFRI(-/-) mice. Silica dependent recruitment of neutrophils to the alveolar space and alveolar protein leak were, however, not altered by the absence of the TNF receptor.
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PMID:Induction of chemokines by low-dose intratracheal silica is reduced in TNFR I (p55) null mice. 1260 44

Fumonisin B1 (FB1), a mycotoxin, is a potent inhibitor of ceramide synthase, and produces organ-, species-, and even gender-specific toxic responses in animals. The hepatotoxic response of FB1 in mice involves accumulation of free sphingoid bases and induction of inflammatory cytokines including tumor necrosis factor alpha (TNFalpha). The FB1-induced hepatotoxic responses were reduced in mice lacking TNFalpha receptor (TNFR) 1 or TNFR2. However, the hepatotoxicity was exacerbated in mice lacking TNFalpha. We therefore investigated the modulation of various other apoptotic signaling factors in TNFalpha-knockout (TKO) mice compared to wild-type (WT) strain after repeated daily subcutaneous injections of 2.25 mg/kg FB1 treatment for 5 days. Expression of various signaling genes in liver was evaluated by ribonuclease protection assay. Expression of CD95-ligand (FasL) was more than doubled in TKO animals after FB1 whereas it was unaltered in the WT group. FB1 did not alter CD95 expression in either strain; however, expressions of TRAIL, and downstream signaling factors FADD, TRADD, and caspase 8 were higher in FB1-treated TKO mice than in the corresponding WT animals. The TKO strain had a higher constitutive expression of apoptotic factors except CD95L. In addition to the CD95 and TNFalpha systems, the expression of apoptotic molecules bcl-2, b-myc, c-myc, bax, max, mad and IL1alpha was induced by FB1 in TKO mice to a greater extent than in WT animals; many of these factors also had a higher constitutive expression in TKO animals than WT mice. Results indicated that FB1 can induce CD95 modulated signaling when TNFalpha is absent. Differential constitutive expression of apoptotic genes in TKO mice may explain their increased sensitivity to FB1. These results are important in characterizing the modulating effect of TNFalpha on apoptotic signaling and in explaining the unexpected sensitivity of mice lacking this cytokine in response to hepatotoxic xenobiotics.
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PMID:Increased expression of CD95-ligand and other apoptotic signaling factors by fumonisin B1, a hepatotoxic mycotoxin, in livers of mice lacking tumor necrosis factor alpha. 1459 19

Chemokines have been implicated in the pathogenesis of many inflammatory processes, including bronchopulmonary dysplasia in mechanically ventilated premature infants. We hypothesized that early expression of the proinflammatory cytokine, tumor necrosis factor alpha (TNFalpha), would be followed by later expression of the downstream chemokine, Grobeta, in the oxygen-injured newborn lung. Reverse transcriptase-polymerase chain reaction (RT-PCR) and ribonuclease protection assay (RPA) were used to assess TNFalpha and Grobeta mRNA expression in lung RNA samples from newborn rabbits exposed to > 95% O2 for 8-9 days, followed by 60% O2 for a further 2-4 weeks or from control rabbits exposed to air. Four lung samples per condition were collected every 2 days from day 0 to day 14, and at days 22 and 36. Rabbit alveolar macrophages (AM) stimulated in vitro with bacterial lipopolysaccharide served as positive controls ( n = 8). Grobeta mRNA expression in rabbit lung samples increased with oxygen exposure until day 8, then returned toward baseline levels. This corresponded to previously described elevations in neutrophil number in the lungs. TNFalpha mRNA expression in lung samples was below the limit of detection by RPA and showed no upregulation in hyperoxic lung samples by RT-PCR. TNFalpha activity was assessed in lung lavage ( n = 2 samples per condition per time) using an L929 cell line bioassay and was not increased in hyperoxic animals. The expression of Grobeta mRNA without antecedent or concurrent TNFalpha mRNA expression or activity makes it unlikely that Grobeta in the hyperoxic newborn rabbit lung is elaborated in response to a stimulus by TNFalpha.
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PMID:Effects of hyperoxia on tumor necrosis factor alpha and Grobeta expression in newborn rabbit lungs. 1474 38

Brain ribonuclease (BRB) is a member of the ribonuclease A superfamily that is constitutively expressed in a range of tissues and is the functional homolog of human ribonuclease 1. This study was designed to characterize BRB gene expression in granulosa cells (GCs) during development of bovine dominant ovarian follicles and to determine the hormonal regulation of BRB in GCs. Estrous cycles of Holstein cows (n = 18) were synchronized, and cows were ovariectomized on either day 3 to 4 or day 5 to 6 after ovulation during dominant follicle growth and selection. Ovaries were collected, follicular fluid (FFL) was aspirated, and GCs were collected for RNA isolation and quantitative polymerase chain reaction. Follicles were categorized as small (1-5 mm; pooled per ovary), medium (5-8 mm; individually collected), or large (8.1-17 mm; individually collected) based on surface diameter. Estradiol (E2) and progesterone (P4) levels were measured by radioimmunoassay (RIA) in FFL. Abundance of BRB messenger RNA (mRNA) in GCs was 8.6- to 11.8-fold greater (P < 0.05) in small (n = 31), medium (n = 66), and large (n = 33) subordinate E2-inactive (FFL E2 < P4) follicles than in large (n = 16) dominant E2-active (FFL E2 > P4) follicles. In the largest 4 follicles, GCs BRB mRNA abundance was negatively correlated (P < 0.01) with FFL E2 (r = -0.65) and E2:P4 ratio (r = -0.46). In experiment 2, GCs from large (8-22 mm diameter) and small (1-5 mm diameter) follicles were treated with insulin-like growth factor 1 (IGF1; 0 or 30 ng/mL) and/or tumor necrosis factor alpha (0 or 30 ng/mL); IGF1 increased (P < 0.05) BRB mRNA abundance, and tumor necrosis factor alpha decreased (P < 0.001) the IGF1-induced BRB mRNA abundance in large-follicle GCs. In experiment 3 to 6, E2, follicle-stimulating hormone, fibroblast growth factor 9, cortisol, wingless 3A, or sonic hedgehog did not affect (P > 0.10) abundance of BRB mRNA in GCs; thyroxine and luteinizing hormone increased (P < 0.05), whereas prostaglandin E2 (PGE2) decreased (P < 0.05) BRB mRNA abundance in small-follicle GCs. Treatment of small-follicle GCs with recombinant human RNase1 increased (P < 0.05) GCs numbers and E2 production. In conclusion, BRB is a hormonally and developmentally regulated gene in bovine GCs and may regulate E2 production during follicular growth in cattle.
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PMID:Changes in brain ribonuclease (BRB) messenger RNA in granulosa cells (GCs) of dominant vs subordinate ovarian follicles of cattle and the regulation of BRB gene expression in bovine GCs. 2677 65