scholarly journals Ghrelin Increases Neuropeptide Y and Agouti-Related Peptide Gene Expression in the Arcuate Nucleus in Rat Hypothalamic Organotypic Cultures

Endocrinology ◽  
2006 ◽  
Vol 147 (11) ◽  
pp. 5102-5109 ◽  
Author(s):  
Motomitsu Goto ◽  
Hiroshi Arima ◽  
Minemori Watanabe ◽  
Masayuki Hayashi ◽  
Ryouichi Banno ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Neuropeptide Y ◽  
Mrna Expression ◽  
Gene Transcription ◽  
Arcuate Nucleus ◽  
De Novo ◽  
Organotypic Cultures ◽  
Related Peptide ◽  
De Novo Protein Synthesis

Ghrelin, which was identified from the rat stomach, is a potent stimulant for food intake. Several lines of evidence suggest that the orexigenic action of ghrelin is mediated via the neuropeptide Y (NPY) neurons in the arcuate nucleus, although the detailed mechanisms by which ghrelin stimulates NPY neurons are not clear. In this study, we examined the gene regulation of NPY and agouti-related peptide (AGRP), another orexigenic peptide synthesized in the NPY neurons, in the arcuate nucleus by ghrelin in hypothalamic organotypic cultures. Incubation of the hypothalamic explants with ghrelin significantly increased NPY and AGRP mRNA expression in the presence, but not absence, of dexamethasone. Glucocorticoids were also necessary for ghrelin action in vivo because an intracerebroventricular injection of ghrelin significantly increased NPY and AGRP mRNA expression in the arcuate nucleus only in sham-operated, but not in adrenalectomized rats. The stimulatory effects of ghrelin on gene expression were not blocked by a sodium channel blocker tetrodotoxin in the organotypic cultures. Ghrelin also increased NPY heteronuclear (hn) RNA expression, the first transcript that has been used as an indicator for gene transcription. The stimulatory effects of ghrelin on NPY gene expression were abolished in the presence of cycloheximide, which blocks translation, suggesting that de novo protein synthesis is required for ghrelin action. These data suggest that ghrelin stimulates NPY and AGRP gene expression independently of action potentials only in the presence of glucocorticoids. Furthermore, our data demonstrate stimulatory action of ghrelin on NPY gene transcription, which requires de novo protein synthesis.

scholarly journals Viral Gene Expression Patterns in Human Herpesvirus 6B-Infected T Cells

2002 ◽  
Vol 76 (15) ◽  
pp. 7578-7586 ◽  
Author(s):  
Bodil Øster ◽  
Per Höllsberg
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Protein Synthesis ◽  
De Novo ◽  
Expression Patterns ◽  
Human Herpesvirus ◽  
Viral Gene Expression ◽  
Polymerase Activity ◽  
Viral Gene ◽  
De Novo Protein Synthesis

ABSTRACT Herpesvirus gene expression is divided into immediate-early (IE) or α genes, early (E) or β genes, and late (L) or γ genes on the basis of temporal expression and dependency on other gene products. By using real-time PCR, we have investigated the expression of 35 human herpesvirus 6B (HHV-6B) genes in T cells infected by strain PL-1. Kinetic analysis and dependency on de novo protein synthesis and viral DNA polymerase activity suggest that the HHV-6B genes segregate into six separate kinetic groups. The genes expressed early (groups I and II) and late (groups V and VI) corresponded well with IE and L genes, whereas the intermediate groups III and IV contained E and L genes. Although HHV-6B has characteristics similar to those of other roseoloviruses in its overall gene regulation, we detected three B-variant-specific IE genes. Moreover, genes that were independent of de novo protein synthesis clustered in an area of the viral genome that has the lowest identity to the HHV-6A variant. The organization of IE genes in an area of the genome that differs from that of HHV-6A underscores the distinct differences between HHV-6B and HHV-6A and may provide a basis for further molecular and immunological analyses to elucidate their different biological behaviors.

Different Regulation of Plasminogen Activator Inhibitor 2 Gene Expression by Phorbol Ester and cAMP in Human Myeloid Leukemia Cell Line PL-21

1994 ◽  
Vol 72 (01) ◽  
pp. 092-097 ◽  
Author(s):  
Kenji Niiya ◽  
Taketoshi Taniguchi ◽  
Masahiro Shinbo ◽  
Tai-ichi Ishikawa ◽  
Shigeki Tazawa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
De Novo ◽  
Mrna Level ◽  
Leukemia Cell ◽  
Plasminogen Activator Inhibitor ◽  
Leukemia Cell Line ◽  
De Novo Protein Synthesis ◽  
Activator Inhibitor ◽  
Myeloid Leukemia Cell

SummaryPrevious studies have shown that protein kinase C (PKC) activators and dibutyryl cyclic AMP (Bt2cAMP) synergistically increase the antigen level of plasminogen activator inhibitor type-2 (PAI-2) in a human myeloid leukemia cell line PL-21. To clarify the mechanism, PAI-2 gene expression induced by phorbol myristate acetate (PMA), a PKC activator, and Bt2cAMP was investigated by Northern blot hybridization using a PAI-2 cDNA probe cloned from a human placental library. The level of PAI-2 mRNA was markedly increased in response to PMA and reached a maximum 5-9 h after stimulation. Nuclear run-on assay revealed an increase in PAI-2 gene transcription in PMA-treated cells. The induction was inhibited by inhibiting de novo protein synthesis with cycloheximide (CHX). cAMP also increased PAI-2 mRNA level in a dose-dependent manner. The increase began within 2 hours and, contrary to the case of PMA, the mRNA levels were maintained. Moreover, cAMP-induced increase in PAI-2 mRNA was not inhibited by CHX, rather enhanced. PMA and cAMP synergistically induced PAI-2 gene expression, which was completely inhibited by CHX. The cells pretreated with PMA for 24 h did not any more respond to stimulation with PMA but responded to cAMP and PAI-2 mRNA level was increased. The apparent half-life of constitutive level PAI-2 mRNA in PL-21 cells, determined by actinomycin-D-decay experiments, was approximately 2 h. Those induced by PMA and cAMP were approximately 5 h and 2 h, respectively. These data suggest that PAI-2 mRNA induced by PMA is relatively stable and the expression requires de novo protein synthesis, whereas cAMP increases PAI-2 mRNA level without affecting the stability and the induction does not require de novo protein synthesis. Judging from these data, PAI-2 gene expression appears to be differently regulated by the PKC and cAMP signalling pathways.

Changes in methionine adenosyltransferase during liver regeneration in the rat

1998 ◽  
Vol 275 (1) ◽  
pp. G14-G21 ◽  
Author(s):  
Zong-Zhi Huang ◽  
Zebin Mao ◽  
Jiaxin Cai ◽  
Shelly C. Lu
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Protein Synthesis ◽  
De Novo ◽  
Mrna Level ◽  
Methionine Adenosyltransferase ◽  
Mrna Levels ◽  
Mrna Stabilization ◽  
De Novo Protein Synthesis ◽  
Mat Gene

Liver-specific and non-liver-specific methionine adenosyltransferase (MAT) are products of two genes (MAT1A and MAT2A, respectively) that catalyze the formation of S-adenosylmethionine (SAM), the principal methyl donor. We previously showed that MAT2A expression was associated with more rapid cell growth. Here we examined changes in hepatic MAT gene expression and related consequences after two-thirds partial hepatectomy (PH) in rats. The mRNA levels of both MAT forms increased from 3 to 6 h, but the MAT1A level then fell below baseline from 12 to 24 h, whereas the MAT2A level remained elevated up to 4 days after PH. The increase in the MAT2A mRNA level was due to increased gene transcription and mRNA stabilization. The change in the MAT1A mRNA level was posttranscriptional and did not require de novo protein synthesis. Changes in MAT activity were consistent with an increased amount of MAT isozymes. SAM levels, the ratio of SAM to S-adenosylhomocysteine (SAH), and DNA methylation fell from 6 to 24 h, whereas SAH levels increased slightly at 12 and 24 h after PH. Both increased SAM utilization and MAT2A gene expression likely contributed to the fall in SAM.

Modulation of Urokinase-type Plasminogen Activator Gene Expression by Inflammatory Cytokines in Human pre-B Lymphoma Cell Line RC-K8

1995 ◽  
Vol 74 (06) ◽  
pp. 1511-1515 ◽  
Author(s):  
Kenji Niiya ◽  
Masahiro Shinbo ◽  
Tetsuo Ozawa ◽  
Yumiko Hayakawa ◽  
Nobuo Sakuragawa
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Plasminogen Activator ◽  
Inflammatory Cytokines ◽  
Gene Transcription ◽  
De Novo ◽  
B Lymphoma ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Upa Mrna

SummaryWe examined the effects of inflammatory cytokines, such as interleukin-lα (IL-lα), interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNFα), transforming growth factor-β (TGFβ) and lipopolysaccharide (LPS), on the urokinase-type plasminogen activator (uPA) gene expression in RC-K8 human pre-B lymphoma cells. Recombinant IL-1α, recombinant IL-1β and LPS but not recombinant IL-6, recombinant TNFα and TGFβ dose-dependently increased uPA accumulation in the conditioned medium. Northern blot analysis revealed that uPA mRNA levels rapidly increased with a peak induction at 2 h after stimulation with IL-lα and IL-1β, but uPA mRNA increase by LPS began at 9 h after stimulation and the increase was maintained until the experiment ended at 24 h. These responses were independent of de novo synthesis, rather amplified in the presence of a protein synthesis inhibitor. The effects by IL-1α and IL-1β were prevented by addition of anti-IL-1α and anti-IL-1β neutralizing antibodies, respectively. In contrast, both antibodies did not prevent LPS-induced uPA gene expression. Therefore, it is unlikely that the effect by LPS is through induction of IL-1. Both IL-1α and IL-1 β rapidly activated uPA gene transcription, but not increased stability of uPA mRNA. These results suggest that both IL-1α and IL-1 β cause a rapid activation of uPA gene transcription in which de novo protein synthesis is not required and that LPS induces uPA gene expression independently of the IL-1 pathway. These modulations of uPA production by inflammatory mediators may be implicated in tumor growth and metastasis.

scholarly journals The role of de novo protein synthesis and SIRT1 in ER stress-induced Atf4 and Chop mRNA expression in mammalian cells

Biochimie ◽  
2017 ◽  
Vol 138 ◽  
pp. 156-167 ◽  
Author(s):  
Stanley M.H. Chan ◽  
Xuechan Zhao ◽  
Abdulsalam Elfowiris ◽  
Cherubina Ratnam ◽  
Terence P. Herbert
Keyword(s):  
Protein Synthesis ◽  
Er Stress ◽  
Mrna Expression ◽  
Mammalian Cells ◽  
De Novo ◽  
De Novo Protein Synthesis ◽  
Expression In Mammalian Cells

scholarly journals Glucocorticoids Increase Neuropeptide Y and Agouti-Related Peptide Gene Expression via Adenosine Monophosphate-Activated Protein Kinase Signaling in the Arcuate Nucleus of Rats

Endocrinology ◽  
2008 ◽  
Vol 149 (9) ◽  
pp. 4544-4553 ◽  
Author(s):  
Hiroshi Shimizu ◽  
Hiroshi Arima ◽  
Minemori Watanabe ◽  
Motomitsu Goto ◽  
Ryoichi Banno ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Neuropeptide Y ◽  
Energy Homeostasis ◽  
Arcuate Nucleus ◽  
Adenosine Monophosphate ◽  
Ampk Signaling ◽  
Related Peptide ◽  
Compound C ◽  
Adrenalectomized Rats

Recent studies suggest that the AMP-activated protein kinase (AMPK) signaling in the hypothalamus is the master regulator of energy balance. We reported in previous studies that glucocorticoids play a permissive role in the regulation of orexigenic neuropeptide Y (Npy) gene expression in the arcuate nucleus. In this study, we examined whether any cross talk occurs between glucocorticoids and AMPK signaling in the hypothalamus to regulate Npy as well as agouti-related peptide (Agrp) gene expression in the arcuate nucleus. In the hypothalamic organotypic cultures, the addition to the medium of the AMPK activator, 5-aminoimidazole-4-carboxamide-1-b-d-ribofuranoside, increased phosphorylated AMPK (p-AMPK) as well as phosphorylated acetyl-coenzyme A carboxylase (p-ACC) in the explants, accompanied by significant increases in Npy and Agrp gene expression in the arcuate nucleus. The incubation with dexamethasone (DEX) also activated AMPK signaling in the explants, accompanied by significant increases in Npy and Agrp gene expression in the arcuate nucleus. The addition of the AMPK inhibitor compound C to the medium, which blocked increases of p-AMPK and p-ACC by DEX, significantly attenuated Npy and Agrp gene expression stimulated by DEX. Furthermore, p-AMPK and p-ACC levels in the arcuate nucleus were significantly decreased in adrenalectomized rats compared with sham-operated rats, and a replacement of glucocorticoids reversed the AMPK signaling in adrenalectomized rats. Thus, our data demonstrated that glucocorticoids up-regulate the Npy and Agrp gene expression in the arcuate nucleus through AMPK signaling, suggesting that the activation of the hypothalamic APMK signaling by glucocorticoids might be essential to the energy homeostasis.

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