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mRNA Synthesis (mrna + synthesis)
Selected AbstractsGATA-3 transduces survival signals in osteoblasts through upregulation of bcl-xL gene expression,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2010Ruei-Ming Chen Abstract GATA-3, a transcription factor, participates in regulating cell development, proliferation, and death. This study was aimed at evaluating the roles of GATA-3 in protecting osteoblasts against oxidative stress,induced apoptotic insults and their possible mechanisms. Pretreatment with nitric oxide (NO) for 24 hours protected osteoblasts, prepared from neonatal rat calvaria, against oxidative stress,induced apoptotic insults. Such protection involved enhancement of Bcl-XL messenger (m)RNA and protein syntheses and the translocation of this antiapoptotic protein from the cytoplasm to mitochondria. GATA-3 was detected in rat osteoblasts, and GATA-3-specific DNA-binding elements exist in the promoter region of the bcl-xL gene. NO preconditioning attenuated oxidative stress,caused suppression of GATA-3 mRNA and protein synthesis and the translocation of this transcription factor from the cytoplasm to nuclei. Application of GATA-3 small interfering (si)RNA into osteoblasts decreased the levels of this transcription factor and simultaneously inhibited Bcl-XL mRNA synthesis. Pretreatment with NO lowered the oxidative stress,caused alteration in the binding of GATA-3 to its specific DNA motifs. Oxidative stress,inhibited Runx2 mRNA expression, but NO preconditioning decreased such inhibition. NO pretreatment time-dependently enhanced the association of GATA-3 with Runx2. Knocking down the translation of GATA-3 using RNA interference significantly decreased the protection of NO preconditioning against oxidative stress,induced alterations of cell morphologies, DNA fragmentation, and cell apoptosis. In comparison, overexpression of GATA-3 could promote NO preconditioning,involved Bcl-XL expression and cell survival. Therefore, this study shows that GATA-3 plays critical roles in mediating survival signals in osteoblasts, possibly through upregulating bcl-xL gene expression. © 2010 American Society for Bone and Mineral Research. [source] Butterfat fatty acids differentially regulate growth and differentiation in Jurkat T-cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2005Paolo Bergamo Abstract Synthetic Conjugated Linoleic Acid mixture (CLA; c9,t11; t10,c12-18:2) has been previously shown to inhibit growth, and enhance apoptosis and IL-2 mRNA synthesis in human lymphoblastic Jurkat T-cells. In this study, two different butterfat types were evaluated and compared for their effects on Jurkat cell viability, oxidative stress, pro-apoptotic activity, and cytokine synthesis: the conventionally produced butterfat (CBF), and organic butterfat (OBF) containing significantly higher amounts of c9,t11 (Rumenic Acid, RA), trans-vaccenic acid (VA; t11-18:1), ,-linolenic acid (ALA), and lower levels of linoleic acid (LA). Results from cell treatment with both butterfat mixtures showed comparable oxidative stress (superoxide production, intracellular GSH depletion,and lipid peroxides yield), NADPH oxidase activation, cytotoxicity (LDH release), and IL-2 transcript level, whereas the effects of enhanced growth-inhibitory and pro-apoptotic activities were associated with OBF treatment. To then investigate each butterfat-induced effect caused by RA, VA, LA, and ALA, cells were exposed to synthetic FA concentrations similar to those from the different butterfats. Higher oxidative stress (superoxide production, intracellular GSH depletion) was induced by ,-linolenic (ALA) and linoleic (LA) incubation (P,<,0.01) and superoxide production was suppressed by specific PKC, inhibitor (Gö 6976) and linked to increased toxicity and IL-2 synthesis inhibition. By contrast, cell treatment with RA increased apoptosis and IL-2 synthesis. These results suggest that a supply of ALA and LA is responsible for BF-induced oxidative stress via PKC,-NADPH oxidase pathway, and that enhanced antiproliferative effects in OBF treated cells is essentially determined by RA-induced pro-apoptotic activity. © 2005 Wiley-Liss, Inc. [source] Growth Hormone-Releasing Peptide-6 Increases Insulin-Like Growth Factor-I mRNA Levels and Activates Akt in RCA-6 Cells as a Model of Neuropeptide Y NeuronesJOURNAL OF NEUROENDOCRINOLOGY, Issue 11 2005L. M. Frago Abstract Chronic systemic administration of growth hormone (GH)-releasing peptide-6 (GHRP-6), an agonist for the ghrelin receptor, to normal adult rats increases insulin-like growth factor (IGF)-I mRNA and phosphorylated Akt (pAkt) levels in various brain regions, including the hypothalamus. Because neuropeptide Y (NPY) neurones of the arcuate nucleus express receptors for ghrelin, we investigated whether these neurones increase their IGF-I and p-Akt levels in response to this agonist. In control rats, immunoreactive pAkt was practically undetectable; however, GHRP-6 increased p-Akt immunoreactivity in the arcuate nucleus, with a subset of neurones also being immunoreactive for NPY. Immunoreactivity for IGF-I was detected in NPY neurones in both experimental groups. To determine if activation of this intracellular pathway is involved in modulation of NPY synthesis RCA-6 cells, an embryonic rat hypothalamic neuronal cell line that expresses NPY was used. We found that GHRP-6 stimulates NPY and IGF-I mRNA synthesis and activates Akt in this cell line. Furthermore, inhibition of Akt activation by LY294002 treatment did not inhibit GHRP-6 induction of NPY or IGF-I synthesis. These results suggest that some of the effects of GHRP-6 may involve stimulation of local IGF-I production and Akt activation in NPY neurones in the arcuate nucleus. However, GHRP-6 stimulation of NPY production does not involve this second messenger pathway. [source] MicroReview: LuxR-type quorum-sensing regulators that are detached from common scentsMOLECULAR MICROBIOLOGY, Issue 5 2010Ching-Sung Tsai Summary The ability of LuxR-type proteins to regulate transcription is controlled by bacterial pheromones, N-acylhomoserine lactones (AHLs). Most LuxR-family proteins require their cognate AHLs for activity, and at least some of them require AHLs for folding and protease resistance. However, a few members of this family are able to fold, dimerize, bind DNA, and regulate transcription in the absence of AHLs; moreover, these proteins are antagonized by their cognate AHLs. Complexes between some of these proteins and their DNA binding sites are disrupted by AHLs in vitro. All such proteins are fairly closely related within the larger LuxR family, indicating that they share a relatively recent common ancestor. The 3, ends of the genes encoding these receptors invariably overlap with the 3, ends of the cognate AHL synthase genes, suggesting additional antagonism at the level of mRNA synthesis, stability or translation. [source] Leishmania donovani -induced macrophages cyclooxygenase-2 and prostaglandin E2 synthesisPARASITE IMMUNOLOGY, Issue 4 2001Claudine Matte Prostaglandin E2 (PGE2) secretion during Leishmania infection has been reported. However, the signalling mechanisms mediating this response are not well understood. Since cyclooxygenase-2 (COX-2) and cytosolic phospholipase A2 (cPLA2) are involved in PGE2 synthesis in response to various stimuli, the implication of these enzymes was evaluated in Leishmania -infected phorbol myristate acetate-differentiated U937 human monocytic cell line. Time-course experiments showed that PGE2 synthesis increased significantly in parallel with COX-2 expression when cells were incubated in the presence of Leishmania donovani promastigotes or lipopolysaccharides (LPS). Increase in cPLA2 mRNA expression was only detected when cells were stimulated with LPS. Indomethacin, genistein, and H7, which are antagonists of COX-2, protein tyrosine kinase (PTK) and protein kinase C (PKC), respectively, inhibited PGE2 production induced by L. donovani and LPS. However, only H7 inhibited COX-2 mRNA synthesis, and there was a significant correlation between PGE2 inhibition and reduced COX-2 expression. Collectively, our results indicate that infection of U937 by L. donovani leads to the generation of PGE2 in part through a PKC-dependent signalling pathway involving COX-2 expression. They further reveal that PTK-dependent events are necessary for Leishmania -induced PGE2 generation, but not for COX-2 expression. A better understanding of the mechanisms by which Leishmania can induce PGE2 production could provide insight into the pathophysiology of leishmaniasis and may help to improve therapeutic approaches. [source] Plant virus infection-induced persistent host gene downregulation in systemically infected leavesTHE PLANT JOURNAL, Issue 2 2008Zoltán Havelda Summary Understanding of virus infection-induced alterations in host plant gene expression and metabolism leading to the development of virus disease symptoms is both scientifically and economically important. Here, we show that viruses belonging to various RNA virus families are able to induce efficient host gene mRNA downregulation (shut-off) in systemically infected leaves. We demonstrate that the host gene mRNA shut-off overlaps spatially with virus-occupied sectors, indicating the direct role of virus accumulation in this phenomenon. The establishment of shut-off was not directly connected to active viral replication or the RNA-silencing machinery. Importantly, the induced shut-off phenomenon persisted for several weeks, resulting in severe deficiency of mRNA for important housekeeping genes in the infected plants. Interestingly, we found that some other RNA viruses do not induce or only slightly induce the shut-off phenomenon for the same set of genes, implicating genetic determination in this process. Nuclear run-on experiments suggest that plant viruses, similarly to animal viruses, mediate suppression of host mRNA synthesis in the nucleus. By investigating various host,virus interactions, we revealed a correlation between the intensity of the shut-off phenomenon and the severity of disease symptoms. Our data suggest that efficient and persistent downregulation of host genes may be an important component of symptom development in certain host,virus interactions. [source] Crystallization and preliminary crystallographic analysis of eukaryotic transcription and mRNA export factor Iws1 from Encephalitozoon cuniculiACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2010Michael Koch Transcription elongation by eukaryotic RNA polymerase II requires the coupling of mRNA synthesis and mRNA processing and export. The essential protein Iws1 is at the interface of these processes through its interaction with histone chaperone and elongation factor Spt6 as well as with complexes involved in mRNA processing and export. Upon crystallization of the evolutionarily conserved domain of Iws1 from Encephalitozoon cuniculi, four different crystal forms were obtained. Three of the crystal forms belonged to space group P21 and one belonged to space group P2221. Preliminary X-ray crystallographic analysis of one of the crystal forms allowed the collection of data to 2.5,Ĺ resolution. [source] Transcriptional Regulation of Caspases in Experimental Pneumococcal MeningitisBRAIN PATHOLOGY, Issue 3 2001Matthias von Mering Apoptosis and necrosis in brain account for neurological sequelae in survivors of bacterial meningitis. In meningitis, several mechanisms may trigger death pathways leading to activation of transcription factors regulating caspases mRNA synthesis. Therefore, we used a multiprobe RNA protection assay (RPA) to examine the expression of 9 caspase-mRNA in the course of experimental Streptococcus pneumoniae meningitis in mouse brain. Caspase-6, -7 and -11 mRNA were elevated 6 hours after infection. 12 hours after infection caspases-1, -2, -8 and -12 mRNA rose. Caspase-14 mRNA was elevated 18 h and caspase-3 mRNA 24 h after infection. In situ hybridization detected caspases-3, -8, -11 and -12 mRNA in neurons of the hippocampal formation and neocortex. Development of sepsis was paralleled by increased transcription of caspases mRNA in the spleen. In TNF,-deficient mice all caspases examined were less upregulated, in TNF-receptor 1/2 knockout mice caspases-1, -2, -7, -11 and -14 mRNA were increased compared to infected control animals. In caspase-1 deficient mice, caspases-11, and -12 mRNA levels did not rise in meningitis indicating the necessity of caspase-1 activating these caspases. Hippocampal formations of newborn mice incubated with heat-inactivated S. pneumoniae R6 showed upregulation of caspase-1, -3, -11 and -12 mRNA. These observations suggest a tightly regulated caspases network at the transcriptional level in addition to the known cascade at the protein level. [source] Plasmodium falciparum infected erythrocytes induce hepcidin (HAMP) mRNA synthesis by peripheral blood mononuclear cellsBRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2009Andrew E. Armitage No abstract is available for this article. [source] Up-regulation of pro-inflammatory genes as adaptation to hypoxia in MCF-7 cells and in human mammary invasive carcinoma microenvironmentCANCER SCIENCE, Issue 4 2010Marco Tafani The role of tumor cells in synthesizing pro-inflammatory molecules is still controversial. Here we report that hypoxic treatment of the MCF-7 human mammary adenocarcinoma cell line induced activation of hypoxia-inducible factor 1, (HIF-1,) and nuclear factor-kappa B (NF-,B). Importantly, hypoxia regulated expression of alarmin receptors such as the receptor for advanced glycation end products (RAGE) and the purinoreceptor (P2X7R), and up-regulated inflammatory response (IR) genes such as the inducible enzymes nitric oxide synthase (NOS2), cycloxygenase (COX2), and the acute-phase protein pentraxin-3 (PTX3). Hypoxia also stimulated chemokine (C-X-C motif) receptor 4 (CXCR4) mRNA synthesis. In fact, the CXCR4 ligand stromal-derived factor-1, (SDF-1,) increased invasion and migration of hypoxic MCF-7 cells. Inhibition of HIF-1, by chetomin and NF-,B by parthenolide reduced mRNA and protein expression of the studied molecules and prevented invasion of hypoxic MCF-7 cells. Moreover, solid invasive mammary tumor microenvironment was analyzed after laser-capture microdissection (LCMD) comparing tumor versus host normal tissue. Nuclear translocation of HIF-1, and NF-,B and up-regulation of IR, CXCR4, estrogen receptor , (ER,), and epithelial growth factor receptor (EGFR) was observed in tumor but not in host normal tissue in the absence of a local inflammatory leukocyte infiltrate. We conclude that under hypoxic conditions MCF-7 cells acquire a pro-inflammatory phenotype, and that solid human mammary carcinoma evidenced a similar activation of HIF-1,, NF-,B, and IR genes in malignant tumor cells as compared to the normal host tissues. We suggest a role for IR activation in the malignant progression of transformed cells. (Cancer Sci 2010; 101: 1014,1023) [source] | |||||||||||||