Hypoxia downregulates tropoelastin gene expression in rat lung fibroblasts by pretranslational mechanisms

1999 ◽  
Vol 277 (3) ◽  
pp. L566-L572 ◽  
Author(s):  
John L. Berk ◽  
Nima Massoomi ◽  
Christine Hatch ◽  
Ronald H. Goldstein
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Actinomycin D ◽  
Lung Fibroblasts ◽  
Mrna Levels ◽  
Rat Lung ◽  
Cell Toxicity ◽  
Chromium Release ◽  
Injured Lung ◽  
Isolated Rat Lung

Elastolytic lung injury disrupts cell barriers, flooding alveoli and producing regional hypoxia. Abnormal O2 tensions may alter repair of damaged elastin fibers. To determine the effect of hypoxia on extravascular elastin formation, we isolated rat lung fibroblasts and cultured them under a variety of O2 conditions. Hypoxia downregulated tropoelastin mRNA in a dose- and time-related fashion while upregulating glyceraldehyde-3-phosphate dehydrogenase mRNA levels. The changes in tropoelastin gene expression were not due to cell toxicity as measured by chromium release and cell proliferation studies. Neither cycloheximide nor actinomycin D abrogated this effect. Hypoxia induced early decreases in tropoelastin mRNA stability; minor suppression of gene transcription occurred later. When returned to 21% O2, tropoelastin mRNA recovered to control levels in part by upregulating tropoelastin gene transcription. Taken together, these data indicate that hypoxia regulates tropoelastin gene expression and may alter repair of acutely injured lung.

Transcriptional and posttranscriptional regulation of CSF-1 gene expression in human monocytes

1988 ◽  
Vol 8 (9) ◽  
pp. 3951-3954
Author(s):  
J Horiguchi ◽  
E Sariban ◽  
D Kufe
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Gene Transcription ◽  
Posttranscriptional Regulation ◽  
Drug Exposure ◽  
Actinomycin D ◽  
Protein Synthesis Inhibitor ◽  
Mrna Levels ◽  
Human Monocytes ◽  
Synthesis Inhibitor

Regulation of CSF-1 gene expression was investigated in human monocytes. CSF-1 transcripts were at low or undetectable levels in resting monocytes. However, in monocytes treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), CSF-1 mRNA was increased by 3 h and reached maximal levels by 12 h of drug exposure. When nuclear run-on assays were used, CSF-1 gene transcription was also at low or undetectable levels in resting monocytes but was activated after TPA exposure. TPA-treated monocytes exposed to actinomycin D further demonstrated that the half-life of the CSF-1 mRNA is 0.9 h. The results also demonstrated that the protein synthesis inhibitor, cycloheximide (CHX), increases CSF-1 mRNA levels in both resting and TPA-treated monocytes. These effects of CHX occurred in the absence of detectable increases in CSF-1 gene transcription. Moreover, treatment of monocytes with CHX and actinomycin D demonstrated that inhibition of protein synthesis is associated with stabilization of the CSF-1 transcript. Taken together, these findings indicated that CSF-1 gene expression is controlled at both transcriptional and posttranscriptional levels in human monocytes.

Regulation of elastin gene transcription by proteasome dysfunction

2005 ◽  
Vol 289 (3) ◽  
pp. C766-C773 ◽  
Author(s):  
Ping-Ping Kuang ◽  
Ronald H. Goldstein
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Proteasome Inhibitors ◽  
Lung Fibroblasts ◽  
Extracellular Matrix Protein ◽  
Mrna Levels ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Elastin Gene

Elastin, a major extracellular matrix protein and the core component of elastic fiber, is essential to maintain lung structural integrity and normal physiological function. We previously found that the downregulation of elastin gene transcription by IL-1β is mediated via activation of NF-κB and CCAAT/enhancer binding protein (C/EBP)β, both targets of the ubiquitin-proteasome pathway. To further investigate the molecular mechanisms that underlie the control of elastin gene expression, we disrupted the ubiquitin-proteasome pathway with specific proteasome inhibitors. We found that specific proteasome inhibitors decreased the steady-state level of elastin mRNA in a dose-responsive manner. Run-on assay and promoter reporter study indicated that the proteasome inhibitor MG-132 repressed the rate of elastin transcription. MG-132 did not affect mRNA levels of NF-κB and C/EBPβ, or the nuclear presence of NF-κB, but markedly increased C/EBPβ isoforms, including liver-enriched transcriptional activating protein and liver-enriched transcriptional inhibitory protein. Addition of cycloheximide blocked these increases and the downregulation of elastin mRNA by MG-132. The MG-132-induced downregulation of elastin transcription was dependent on C/EBPβ expression as assessed with small interfering RNA. These results indicate that the ubiquitin-proteasome pathway plays an essential role in maintaining elastin gene expression in lung fibroblasts. Disruption of this pathway results in the downregulation of tropoelastin transcription via posttranscriptionally induced C/EBPβ isoforms.

scholarly journals Transcriptional and posttranscriptional regulation of CSF-1 gene expression in human monocytes.

1988 ◽  
Vol 8 (9) ◽  
pp. 3951-3954 ◽  
Author(s):  
J Horiguchi ◽  
E Sariban ◽  
D Kufe
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Gene Transcription ◽  
Posttranscriptional Regulation ◽  
Drug Exposure ◽  
Actinomycin D ◽  
Protein Synthesis Inhibitor ◽  
Mrna Levels ◽  
Human Monocytes ◽  
Synthesis Inhibitor

Regulation of CSF-1 gene expression was investigated in human monocytes. CSF-1 transcripts were at low or undetectable levels in resting monocytes. However, in monocytes treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), CSF-1 mRNA was increased by 3 h and reached maximal levels by 12 h of drug exposure. When nuclear run-on assays were used, CSF-1 gene transcription was also at low or undetectable levels in resting monocytes but was activated after TPA exposure. TPA-treated monocytes exposed to actinomycin D further demonstrated that the half-life of the CSF-1 mRNA is 0.9 h. The results also demonstrated that the protein synthesis inhibitor, cycloheximide (CHX), increases CSF-1 mRNA levels in both resting and TPA-treated monocytes. These effects of CHX occurred in the absence of detectable increases in CSF-1 gene transcription. Moreover, treatment of monocytes with CHX and actinomycin D demonstrated that inhibition of protein synthesis is associated with stabilization of the CSF-1 transcript. Taken together, these findings indicated that CSF-1 gene expression is controlled at both transcriptional and posttranscriptional levels in human monocytes.

Nitric oxide increases IL-8 gene transcription and mRNA stability to enhance IL-8 gene expression in lung epithelial cells

2004 ◽  
Vol 287 (4) ◽  
pp. L764-L773 ◽  
Author(s):  
Loretta Sparkman ◽  
Vijayakumar Boggaram
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Protein Kinase ◽  
Epithelial Cells ◽  
Gene Transcription ◽  
Mrna Stability ◽  
Inflammatory Responses ◽  
Lung Epithelial Cells ◽  
Mrna Levels ◽  
Lung Epithelial

Interleukin (IL)-8, a C-X-C chemokine, is a potent chemoattractant and an activator for neutrophils, T cells, and other immune cells. The airway and respiratory epithelia play important roles in the initiation and modulation of inflammatory responses via production of cytokines and surfactant. The association between elevated levels of nitric oxide (NO) and IL-8 in acute lung injury associated with sepsis, acute respiratory distress syndrome, respiratory syncytial virus infection in infants, and other inflammatory diseases suggested that NO may play important roles in the control of IL-8 gene expression in the lung. We investigated the role of NO in the control of IL-8 gene expression in H441 lung epithelial cells. We found that a variety of NO donors significantly induced IL-8 mRNA levels, and the increase in IL-8 mRNA was associated with an increase in IL-8 protein. NO induction of IL-8 mRNA was due to increases in IL-8 gene transcription and mRNA stability. NO induction of IL-8 mRNA levels was not inhibited by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one and KT-5823, inhibitors of soluble guanylate cyclase and protein kinase G, respectively, and 8-bromo-cGMP did not increase IL-8 mRNA levels. This indicated that NO induces IL-8 mRNA levels independently of changes in the intracellular cGMP levels. NO induction of IL-8 mRNA was significantly reduced by inhibitors of extracellular regulated kinase and protein kinase C. IL-8 induction by NO was also reduced by hydroxyl radical scavengers such as dimethyl sulfoxide and dimethylthiourea, indicating the involvement of hydroxyl radicals in the induction process. NO induction of IL-8 gene expression could be a significant contributing factor in the initiation and induction of inflammatory response in the respiratory epithelium.

scholarly journals Feedback Inhibition of Human Scavenger Receptor Class B Type I Gene Expression by Glucocorticoid in Adrenal and Ovarian Cells

Endocrinology ◽  
2010 ◽  
Vol 151 (7) ◽  
pp. 3214-3224 ◽  
Author(s):  
Sofia Mavridou ◽  
Maria Venihaki ◽  
Olga Rassouli ◽  
Christos Tsatsanis ◽  
Dimitris Kardassis
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Feedback Inhibition ◽  
Steroid Hormone ◽  
Scavenger Receptor ◽  
Type I ◽  
Mrna Levels ◽  
Ovarian Cells ◽  
Scavenger Receptor Class ◽  
Class B

Scavenger receptor class B type I (SR-BI) facilitates the reverse transport of excess cholesterol from peripheral tissues to the liver via high-density lipoproteins. In steroidogenic tissues, SR-BI supplies cholesterol for steroid hormone production. We show here that the transcription of the human SR-BI gene is subject to feedback inhibition by glucocorticoid in adrenal and ovarian cells. SR-BI mRNA levels were increased in adrenals from corticosterone-insufficient Crh−/− mice, whereas corticosterone replacement by oral administration inhibited SR-BI gene expression in these mice. SR-BI mRNA levels were increased in adrenals from wild-type mice treated with metyrapone, a drug that blocks corticosterone synthesis. Experiments in adrenocortical H295R and ovarian SKOV-3 cells using cycloheximide and siRNA-mediated gene silencing revealed that glucocorticoid-mediated inhibition of SR-BI gene transcription requires de novo protein synthesis and the glucocorticoid receptor (GR). No direct binding of GR to the SR-BI promoter could be demonstrated in vitro and in vivo, suggesting an indirect mechanism of repression of SR-BI gene transcription by GR in adrenal cells. Deletion analysis established that the region of the human SR-BI promoter between nucleotides −201 and −62 is sufficient to mediate repression by glucocorticoid. This region contains putative binding sites for transcriptional repressors that could play a role in SR-BI gene regulation in response to glucocorticoid. In summary, this is the first report showing that glucocorticoid suppress SR-BI expression suggesting that steroidogenic tissues maintain steroid hormone homeostasis by prohibiting SR-BI-mediated high-density lipoprotein cholesterol uptake when the endogenous levels of glucocorticoid are elevated.

scholarly journals Glucocorticoid hormones downregulate histidine decarboxylase mRNA and enzyme activity in rat lung

1998 ◽  
Vol 275 (2) ◽  
pp. L407-L413 ◽  
Author(s):  
Cynthia A. Zahnow ◽  
Pertti Panula ◽  
Atsushi Yamatodani ◽  
David E. Millhorn
Keyword(s):  
Gene Expression ◽  
Enzyme Activity ◽  
Adrenal Gland ◽  
Histidine Decarboxylase ◽  
Mrna Levels ◽  
Glucocorticoid Hormones ◽  
Rat Lung ◽  
Dexamethasone Treatment ◽  
Inflammatory Disorders ◽  
Corticosterone Treatment

Histidine decarboxylase (HDC) is the primary enzyme regulating histamine biosynthesis. Histamine contributes to the pathogenesis of chronic inflammatory disorders such as asthma. Because glucocorticoids are effective in the treatment of asthma, we examined the effects of 6 h of exogenously administered dexamethasone (0.5–3,000 μg/kg ip), corticosterone (0.2–200 mg/kg ip), or endogenously elevated corticosterone (via exposure of rats to 10% oxygen) on HDC expression in the rat lung. HDC transcripts were decreased ∼73% with dexamethasone treatment, 57% with corticosterone treatment, and 50% with exposure to 10% oxygen. Likewise, HDC enzyme activity was decreased 80% by treatment with dexamethasone and corticosterone and 60% by exposure to 10% oxygen. Adrenalectomy prevented the decreases in HDC mRNA and enzyme activity observed in rats exposed to 10% oxygen, suggesting that the adrenal gland is necessary for the mediation of hypoxic effects on HDC gene expression. These results demonstrate that corticosteroids initiate a process that leads to the decrease of HDC mRNA levels and enzyme activity in rat lung.

Dexamethasone stimulates transcription of the Na+-K+-ATPase β1gene in adult rat lung epithelial cells

2003 ◽  
Vol 285 (3) ◽  
pp. L593-L601 ◽  
Author(s):  
Hong Hao ◽  
Christine H. Wendt ◽  
Gurpreet Sandhu ◽  
David H. Ingbar
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Regulatory Elements ◽  
Lung Epithelial Cells ◽  
Mrna Levels ◽  
Rat Lung ◽  
Alveolar Epithelial ◽  
Adult Rat ◽  
Atpase Gene ◽  
Lung Epithelial

Na+-K+-ATPase plays an essential role in active alveolar epithelial fluid resorption. In fetal and adult alveolar epithelial cells, glucocorticoids (GC) increase Na+-K+-ATPase activity and mRNA levels. We sought to define the mechanism of Na+-K+-ATPase gene upregulation by GC. In a rat alveolar epithelial cell line (RLE), dexamethasone (Dex) increased β1-subunit Na+-K+-ATPase mRNA expression two- to threefold within 3 h after exposure to the GC. The increased gene expression was due to increased transcription as demonstrated by nuclear run-on assays, whereas mRNA stability remained unchanged. Transient transfection of 5′ deletion mutants of a β1promoter-reporter construct demonstrated a 1.5- to 2.2-fold increase in promoter activity by Dex. All of the 5′ deletion constructs contained partial or palindromic GC regulatory elements (GRE) and responded to GC. The increased expression of promoter reporter was inhibited by RU-486, a GC receptor (GR) antagonist, suggesting the involvement of GR. The palindromic GRE at -631 demonstrated Dex induction in a heterologous promoter construct. Gel mobility shift assays using RLE nuclear extracts demonstrated specific binding to this site and the presence of GR. We conclude that GC directly stimulate transcription of Na+-K+-ATPase β1gene expression in adult rat lung epithelial cells through a GR-dependent mechanism that can act at multiple sites.

scholarly journals Transcriptional and posttranscriptional modulation of human neutrophil elastase gene expression

Blood ◽  
1992 ◽  
Vol 79 (10) ◽  
pp. 2733-2740 ◽  
Author(s):  
K Yoshimura ◽  
RG Crystal
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Gene Transcription ◽  
Neutrophil Elastase ◽  
Human Neutrophil ◽  
Leukemia Cell Line ◽  
Human Neutrophil Elastase ◽  
Mrna Levels ◽  
Mrna Transcript ◽  
Lineage Differentiation

Abstract Human neutrophil elastase (NE), a 29-Kd potent serine protease stored in azurophilic granules of mature neutrophils, is coded for by the NE gene, a single copy gene with 5 exons spanning a 6-kb segment of chromosome 11 at q14. With the knowledge that the NE gene expression is limited to early myeloid cell differentiation, mechanisms modulating expression of the NE gene were evaluated in the HL-60 promyelocytic leukemia cell line, a model of early bone marrow precursor cells. Consistent with the presence of NE messenger RNA (mRNA) transcripts in undifferentiated HL-60 cells, nuclear transcription run-on analyses showed that HL-60 cells actively transcribed the NE gene. However, the transcription rate of the NE gene was relatively low, only 40% of the myeloperoxidase gene, a gene expressed in parallel with NE. When induced toward the mononuclear phagocytic lineage with phorbol 12- myristate 13-acetate (PMA), HL-60 cells exhibited marked suppression of NE gene transcription, declining to 17% of the resting rate within 2 days. Induction toward mononuclear phagocytic lineage differentiation caused no change in NE mRNA transcript half-life (T1/2), but mRNA levels decreased markedly over time, with levels undetectable 1.5 days after PMA stimulation. In contrast, when induced toward the myelocytic lineage with dimethyl sulfoxide, the rate of NE gene transcription increased 1.9-fold within 5 days. Interestingly, the mRNA transcript levels increased 2.5-fold by 5 days despite the fact that induction toward myelocytic lineage differentiation was accompanied by a marked reduction of NE mRNA transcript T1/2. Together, these observations suggest that the NE gene expression during bone marrow differentiation is modulated mainly at the transcriptional level, with some posttranscriptional modulation contributing, particularly during myelocytic lineage differentiation.

scholarly journals Tumor Necrosis Factor-α Stimulates Lactate Dehydrogenase A Expression in Porcine Cultured Sertoli Cells: Mechanisms of Action

Endocrinology ◽  
1999 ◽  
Vol 140 (7) ◽  
pp. 3054-3062 ◽  
Author(s):  
Fayçal Boussouar ◽  
Renée Grataroli ◽  
Jingwei Ji ◽  
Mohamed Benahmed
Keyword(s):  
Mrna Expression ◽  
Gene Transcription ◽  
Sertoli Cells ◽  
Tumor Necrosis ◽  
Actinomycin D ◽  
Lactate Production ◽  
Mrna Levels ◽  
Kinase C ◽  
Factor Α ◽  
Necrosis Factor

Abstract In the present study, we investigated the regulatory action of tumor necrosis factor-α (TNFα) on lactate dehydrogenase A (LDH A), a key enzyme involved in lactate production. To this end, use was made of a primary culture system of porcine testicular Sertoli cells. TNFα stimulated LDH A messenger RNA (mRNA) expression in a dose (ED50 = 2.5 ng/ml; 0.1 nm TNFα)-dependent manner. This stimulatory effect was time dependent, with an effect detected after 6 h of TNFα treatment and maximal after 48 h of exposition (5-fold; P < 0.001). The direct effect of TNFα on LDH A mRNA could not be accounted for by an increase in mRNA stability (half-life = 9 h), but was probably due to an increase in LDH A gene transcription. Inhibitors of protein synthesis (cycloheximide), gene transcription (actinomycin D and dichlorobenzimidazole riboside), tyrosine kinase (genistein), and protein kinase C (bisindolylmaleimide) abrogated completely (actinomycin D, dichlorobenzimidazole riboside, cycloheximide, and genistein) or partially (bisindolylmaleimide) TNFα-induced LDH A mRNA expression. These observations suggest that the stimulatory effect of TNFα on LDH A mRNA expression requires protein synthesis and may involve a protein tyrosine kinase and protein kinase C. In addition, we report that LDH A mRNA levels were increased in Sertoli cells treated with FSH. However, although the cytokine enhances LDH A mRNA levels through increased gene transcription, the hormone exerts its stimulatory action through an increase in LDH A mRNA stability. The regulatory actions of the cytokine and the hormone on LDH A mRNA levels and therefore on lactate production may operate in the context of the metabolic cooperation between Sertoli and postmeiotic germ cells in the seminiferous tubules.

Tumor necrosis factor inhibits growth hormone-mediated gene expression in hepatocytes

2006 ◽  
Vol 291 (1) ◽  
pp. G35-G44 ◽  
Author(s):  
Tamer Ahmed ◽  
Gladys Yumet ◽  
Margaret Shumate ◽  
Charles H. Lang ◽  
Peter Rotwein ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Hormone ◽  
Mrna Expression ◽  
Gene Transcription ◽  
Protein Tyrosine Phosphatases ◽  
Mrna Levels ◽  
Inhibitory Effects ◽  
Protein Levels ◽  
Mrna Induction ◽  
Igf I

Growth hormone (GH) stimulates STAT5 phosphorylation by JAK2, which activates IGF-I and serine protease inhibitor 2.1 (Spi 2.1) transcription, whereas STAT5 dephosphorylation by protein tyrosine phosphatases (PTPs) terminates this signal. We hypothesized that the inhibitory effects of TNF on GH signaling and gene transcription were responsible for hepatic GH resistance. CWSV-1 hepatocytes were treated with TNF, pervanadate (a PTP inhibitor), or both, before GH stimulation. Total and tyrosine-phosphorylated JAK2, STAT5, ERK1/2, SHP-1 and SHP-2, IGF-I, and Spi 2.1 mRNA levels were measured. GH stimulated STAT5 and ERK1/2 phosphorylation, IGF-I, and Spi 2.1 mRNA expression. TNF attenuated JAK2/STAT5 and ERK1/2 phosphorylation and IGF-I and Spi 2.1 mRNA expression following GH stimulation. SHP-1 and SHP-2 protein levels were unaltered by TNF or GH, and the GH-induced increase in SHP-1 PTP activity was not further increased by TNF. In TNF-treated cells, pervanadate restored STAT5 and ERK1/2 phosphorylation to control levels following GH stimulation but did not restore IGF-I or Spi 2.1 mRNA induction. Cells transfected with a Spi 2.1 promoter-luciferase vector demonstrate a 50-fold induction in luciferase activity following GH stimulation or cotransfection with a constitutively active STAT5 vector. TNF prevented the induction of Spi 2.1 promoter activity by GH and the STAT5 construct. We conclude that TNF does not inhibit GH activity by inducing SHP-1 or -2 expression and that correction of GH signaling defects in TNF-treated cells by pervanadate does not restore GH-induced gene expression. The inhibitory effects of TNF on GH-mediated gene transcription appear independent of STAT5 activity and previously identified abnormalities in JAK2/STAT5 signaling.

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