scholarly journals Cross Talk between PKC and CREB in the Induction of COX-2 by PGF2α in Human Amnion Fibroblasts

Endocrinology ◽  
2012 ◽  
Vol 153 (10) ◽  
pp. 4938-4945 ◽  
Author(s):  
C. M. Guo ◽  
N. Kasaraneni ◽  
K. Sun ◽  
L. Myatt
Keyword(s):  
Prostaglandin F2α ◽  
Dominant Negative ◽  
Fetal Membranes ◽  
Camp Response Element ◽  
Human Amnion ◽  
Rate Limiting Step ◽  
Inducible Synthesis ◽  
Fp Receptor ◽  
Cox 2 ◽  
Interfering Rna

Abstract Compelling evidence indicates a crucial role of prostaglandin F2α (PGF2α) in parturition. Both the maternal and fetal sides of the fetal membranes synthesize PGF2α, which exerts effects via the prostaglandin F2α receptor (FP) that is coupled to the activation of protein kinase C (PKC). Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step of the inducible synthesis of prostaglandin. Although activation of PKC is known to induce COX-2 expression, it is not clear whether PGF2α can induce COX-2 via FP receptor-coupled PKC activation. COX-2 promoter carries a cAMP-response element (CRE) and phosphorylation of CRE binding protein 1 (CREB1) is associated with COX-2 expression in human amnion fibroblasts. We demonstrated that human amnion fibroblasts produced PGF2α and expressed FP receptor. PGF2α increased COX-2 expression and CREB1 phosphorylation, which could be blocked by either the FP receptor antagonist AL8810 or PKC inhibitor Ro31-7549. The PKC activator, phorbol-12-myristate-13-acetate (PMA), could mimic the induction of COX-2 and CREB1 phosphorylation. The induction of COX-2 by PGF2α and PMA could be attenuated by the small interfering RNA-mediated knockdown of CREB1 expression or overexpressing dominant-negative CREB1. A chromatin immunoprecipitation assay showed that the binding of CREB1 to the COX-2 promoter was increased by PGF2α and PMA in amnion fibroblasts. In conclusion, we provide evidence that PGF2α induces COX-2 expression via the FP receptor and phosphorylates CREB1 by PKC, thus increasing CREB1 binding to the COX-2 promoter and the expression of COX-2 in human amnion fibroblasts. This feed-forward loop may be crucial for the production of prostaglandins in the fetal membranes prior to the onset of labor.

scholarly journals Expression of cyclo-oxygenase types-1 and -2 in human fetal membranes throughout pregnancy

1999 ◽  
Vol 22 (2) ◽  
pp. 125-130 ◽  
Author(s):  
D Slater ◽  
W Dennes ◽  
R Sawdy ◽  
V Allport ◽  
P Bennett
Keyword(s):  
Mrna Expression ◽  
Gestational Age ◽  
Prostaglandin Synthesis ◽  
Fetal Membranes ◽  
Activity Levels ◽  
Third Trimester ◽  
Human Amnion ◽  
Human Labour ◽  
Cox 2 ◽  
Cox 1

Human labour is associated with increased prostaglandin synthesis within the fetal membranes. We have studied the expression of the two isoforms of the central prostaglandin synthetic enzyme, cyclo-oxygenase (COX-1 and COX-2), in human fetal membranes throughout pregnancy, at mRNA, protein and activity levels. COX-1 mRNA expression was low in human amnion and chorion-decidua and did not change with gestational age. COX-2 mRNA expression in fetal membranes increased with gestational age, with significant up-regulation prior to the onset of labour and in association with labour. Protein concentrations of COX-1 did not change, whilst concentrations of COX-2 increased from the first to the third trimester. COX activity increased with gestational age and in association with labour, although prostaglandin production in fetal membranes collected after labour was reduced, suggesting reduced substrate supply. These data suggest that it is up-regulation of COX-2, rather than of COX-1, which mediates increased prostaglandin synthesis within the fetal membranes at term. Much of the increase in COX-2 expression precedes the onset of labour, suggesting that it is a cause, rather than a consequence, of labour.

scholarly journals A Positive Feedback Loop that Regulates Cyclooxygenase-2 Expression and Prostaglandin F2α Synthesis via the F-Series-Prostanoid Receptor and Extracellular Signal-Regulated Kinase 1/2 Signaling Pathway

Endocrinology ◽  
2005 ◽  
Vol 146 (11) ◽  
pp. 4657-4664 ◽  
Author(s):  
Henry N. Jabbour ◽  
Kurt J. Sales ◽  
Sheila C. Boddy ◽  
Richard A. Anderson ◽  
Alistair R. W. Williams
Keyword(s):  
Positive Feedback ◽  
Feedback Loop ◽  
Endometrial Adenocarcinoma ◽  
Prostaglandin F2α ◽  
Receptor Activation ◽  
Receptor Interaction ◽  
Dominant Negative Mutant ◽  
Positive Feedback Loop ◽  
Fp Receptor ◽  
Cox 2

Cyclooxygenase (COX) enzymes catalyze the biosynthesis of eicosanoids, including prostaglandin (PG) F2α. PGF2α exerts its autocrine/paracrine function by coupling to its G protein-coupled receptor [F-series-prostanoid (FP) receptor] to initiate cell signaling and target gene transcription. In the present study, we found elevated expression of COX-2 and FP receptor colocalized together within the neoplastic epithelial cells of endometrial adenocarcinomas. We investigated a role for PGF2α-FP receptor interaction in modulating COX-2 expression and PGF2α biosynthesis using an endometrial adenocarcinoma cell line stably transfected with the FP receptor cDNA (FPS cells). PGF2α-FP receptor activation rapidly induced COX-2 promoter, mRNA, and protein expression in FPS cells. These effects of PGF2α on the expression of COX-2 could be abolished by treatment of FPS cells with an FP receptor antagonist (AL8810) and chemical inhibitor of ERK1/2 kinase (PD98059), or by inactivation of ERK1/2 signaling with dominant-negative mutant isoforms of Ras or ERK1/2 kinase. We further confirmed that elevated COX-2 protein in FPS cells could biosynthesize PGF2αde novo to promote a positive feedback loop to facilitate endometrial tumorigenesis. Finally, we have shown that PGF2α could potentiate tumorigenesis in endometrial adenocarcinoma explants by inducing the expression of COX-2 mRNA.

scholarly journals Induction of PGF2α Synthesis by Cortisol Through GR Dependent Induction of CBR1 in Human Amnion Fibroblasts

Endocrinology ◽  
2014 ◽  
Vol 155 (8) ◽  
pp. 3017-3024 ◽  
Author(s):  
Chunming Guo ◽  
Wangsheng Wang ◽  
Chao Liu ◽  
Leslie Myatt ◽  
Kang Sun
Keyword(s):  
Rna Polymerase Ii ◽  
Critical Role ◽  
Prostaglandin F2α ◽  
Fetal Membranes ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Human Amnion ◽  
Antagonist Ru486 ◽  
Human Parturition

Abundant evidence indicates a pivotal role of prostaglandin F2α (PGF2α) in human parturition. Both the fetal and maternal sides of the fetal membranes synthesize PGF2α. In addition to the synthesis of PGF2α from PGH2 by PGF synthase (PGFS), PGF2α can also be converted from PGE2 by carbonyl reductase 1 (CBR1). Here, we showed that there was concurrent increased production of cortisol and PGF2α in association with the elevation of CBR1 in human amnion obtained at term with labor versus term without labor. In cultured primary human amnion fibroblasts, cortisol (0.01–1μM) increased PGF2α production in a concentration-dependent manner, in parallel with elevation of CBR1 levels. Either siRNA-mediated knockdown of glucocorticoid receptor (GR) expression or GR antagonist RU486 attenuated the induction of CBR1 by cortisol. Chromatin immunoprecipitation (ChIP) showed an increased enrichment of both GR and RNA polymerase II to CBR1 promoter. Knockdown of CBR1 expression with siRNA or inhibition of CBR1 activity with rutin decreased both basal and cortisol-stimulated PGF2α production in human amnion fibroblasts. In conclusion, CBR1 may play a critical role in PGF2α synthesis in human amnion fibroblasts, and cortisol promotes the conversion of PGE2 into PGF2α via GR-mediated induction of CBR1 in human amnion fibroblasts. This stimulatory effect of cortisol on CBR1 expression may partly explain the concurrent increases of cortisol and PGF2α in human amnion tissue with labor, and these findings may account for the increased production of PGF2α in the fetal membranes prior to the onset of labor.

scholarly journals Expression of Progesterone Receptor A form and Its Role in the Interaction of Progesterone with Cortisol on Cyclooxygenase-2 Expression in Amnionic Fibroblasts

2009 ◽  
Vol 94 (12) ◽  
pp. 5085-5092 ◽  
Author(s):  
C. M. Guo ◽  
X. O. Zhu ◽  
X. T. Ni ◽  
Z. Yang ◽  
L. Myatt ◽  
...  
Keyword(s):  
Progesterone Receptor ◽  
Small Interfering Rna ◽  
Prostaglandin Synthesis ◽  
Cyclooxygenase 2 ◽  
Receptor Subtypes ◽  
Term Pregnancy ◽  
Human Amnion ◽  
Cox 2 ◽  
Exogenous Progesterone ◽  
Interfering Rna

Context: Human amnion fibroblasts produce abundant prostaglandins toward the end of gestation, which is believed to be one of the major events leading to parturition. Glucocorticoids have been shown to up-regulate cyclooxygenase-2 (COX-2) expression, the crucial enzyme catalyzing prostaglandin synthesis, in human amnion fibroblasts. Although a major propregnancy hormone, the effect of progesterone and the associated progesterone receptor subtypes in the regulation of both basal and glucocorticoid-induced COX-2 expression in human amnion fibroblasts have not been resolved. Methods and Results: Cultured human amnion fibroblasts prepared from the fetal membranes at term pregnancy without labor mainly expressed the progesterone receptor A form (PRA). Inhibition of endogenous progesterone production with trilostane or knockdown of PRA expression with small interfering RNA significantly enhanced the glucocorticoid receptor (GR)-mediated COX-2 induction by cortisol, whereas overexpression of PRA attenuated the induction by cortisol. Co-immunoprecipitation assay revealed PRA in the GR protein complex. Although exogenous progesterone did not alter COX-2 expression under basal conditions, it attenuated cortisol-induced COX-2 expression at concentrations about 10- to 50-fold higher, which might be achieved by competition with cortisol for GR. Conclusions: We demonstrated in this study that endogenous progesterone might counteract the induction of prostaglandin synthesis by cortisol via PRA transdominant repression of GR function, whereas high levels of progesterone might further inhibit the induction by cortisol via competitive binding to GR in human amnion fibroblasts. These inhibitory actions of progesterone and PRA on glucocorticoids and GR may partly explain the inconsistent effects of glucocorticoids on parturition in humans.

scholarly journals Role of glucocorticoid receptor and CCAAT/enhancer-binding protein α in the feed-forward induction of 11β-hydroxysteroid dehydrogenase type 1 expression by cortisol in human amnion fibroblasts

2007 ◽  
Vol 195 (2) ◽  
pp. 241-253 ◽  
Author(s):  
Zhen Yang ◽  
Chunming Guo ◽  
Ping Zhu ◽  
Wenjiao Li ◽  
Leslie Myatt ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Mrna Expression ◽  
Promoter Region ◽  
Molecular Mechanisms ◽  
Hydroxysteroid Dehydrogenase ◽  
Dominant Negative ◽  
Forward Induction ◽  
Human Amnion ◽  
Feed Forward

The amount of cortisol available to its receptors is increased by the pre-receptor enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) which converts cortisone to cortisol. We examined the molecular mechanisms of the feedback effect of cortisol on 11β-HSD1 mRNA expression in human amnion fibroblasts. Our data showed that cortisol-induced 11β-HSD1 mRNA expression dose dependently in amnion fibroblasts, which could be completely blocked both by the mRNA transcription inhibitor 5,6-dichlorobenzimidazole riboside and by the glucocorticoid receptor (GR) antagonist RU486, and partially blocked by global inhibition of CCAAT/enhancer-binding proteins (C/EBPs) with transfection of C/EBP-specific dominant-negative expression CMV500 plasmid (AC/EBP) into the cells. Likewise, the induction of the promoter activity by cortisol could also be completely blocked by RU486 and partially by AC/EBP transfection. Progressive 5′ deletion of the 11β-HSD1promoter located the region responsible for cortisol’s induction within −204 bp upstream to the transcription start site. Specific nucleotide mutations of the putative glucocorticoid responsive element or CCAAT in this promoter region attenuated the induction by cortisol. Moreover, chromatin immunoprecipitation assay and electrophoretic mobility shift assay showed that GR and C/EBPα but not C/EBPβ could bind this promoter region upon cortisol stimulation of amnion fibroblasts. In conclusion, we demonstrated that GR and C/EBPα were involved in cortisol-induced 11β-HSD1 mRNA expression via binding to 11β-HSD1 promoter in amnion fibroblasts, which may cast a feed-forward production of cortisol in the fetal membranes at the end of gestation.

PGE2 potentiates tonicity-induced COX-2 expression in renal medullary cells in a positive feedback loop involving EP2-cAMP-PKA signaling

2009 ◽  
Vol 296 (1) ◽  
pp. C75-C87 ◽  
Author(s):  
Daniela Steinert ◽  
Christoph Küper ◽  
Helmut Bartels ◽  
Franz-X. Beck ◽  
Wolfgang Neuhofer
Keyword(s):  
Osmotic Stress ◽  
Cell Survival ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Mdck Cells ◽  
Dominant Negative ◽  
Dibutyryl Camp ◽  
Positive Feedback Loop ◽  
Cox 2 ◽  
Medullary Cells

Cyooxygenase-2 (COX-2)-derived PGE2 is critical for the integrity and function of renal medullary cells during antidiuresis. The present study extended our previous finding that tonicity-induced COX-2 expression is further stimulated by the major COX-2 product PGE2 and investigated the underlying signaling pathways and the functional relevance of this phenomenon. Hyperosmolality stimulated COX-2 expression and activity in Madin-Darby canine kidney (MDCK) cells, a response that was further increased by PGE2-cAMP signaling, suggesting the existence of a positive feedback loop. This effect was diminished by AH-6809, an EP2 antagonist, and by the PKA inhibitor H-89, but not by AH-23848, an EP4 antagonist. The effect of PGE2 was mimicked by forskolin and dibutyryl-cAMP, suggesting that the stimulatory effect of PGE2 on COX-2 is mediated by a cAMP-PKA-dependent mechanism. Accordingly, cAMP-responsive element (CRE)-driven reporter activity paralleled the effects of PGE2, AH-6809, AH-23848, H-89, forskolin, and dibutyryl-cAMP on COX-2 expression. In addition, the stimulatory effect of PGE2 on tonicity-induced COX-2 expression was blunted in cells transfected with dominant-negative CRE binding (CREB) protein, as was the case in a COX-2 promoter reporter construct in which a putative CRE was deleted. Furthermore, PGE2 resulted in PKA-dependent phosphorylation of the pro-apoptotic protein Bad at Ser155, a mechanism that is known to inactivate Bad, which coincided with reduced caspase-3 activity during osmotic stress. Conversely, pharmacological interruption of the PGE2-EP2-cAMP-PKA pathway abolished Ser155 phosphorylation of Bad and blunted the protective effect of PGE2 on cell survival during osmotic stress. These observations indicate the existence of a positive feedback loop of PGE2 on COX-2 expression during osmotic stress, an effect that apparently is mediated by EP2-cAMP-PKA signaling, and that contributes to cell survival under hypertonic conditions.

scholarly journals GH1 Splicing Is Regulated by Multiple Enhancers Whose Mutation Produces a Dominant-Negative GH Isoform That Can Be Degraded by Allele-Specific Small Interfering RNA (siRNA)

Endocrinology ◽  
2004 ◽  
Vol 145 (6) ◽  
pp. 2988-2996 ◽  
Author(s):  
Robin C. C. Ryther ◽  
Alex S. Flynt ◽  
Bryan D. Harris ◽  
John A. Phillips ◽  
James G. Patton
Keyword(s):  
Small Interfering Rna ◽  
Dominant Negative ◽  
Allele Specific ◽  
Interfering Rna
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