Regulation of 11β-hydroxysteroid dehydrogenase type 2 activity and mRNA in human choriocarcinoma cells

1996 ◽  
Vol 16 (3) ◽  
pp. 269-275 ◽  
Author(s):  
M M Pasquarette ◽  
P M Stewart ◽  
M L Ricketts ◽  
K Imaishi ◽  
J I Mason
Keyword(s):  
Protein Kinase ◽  
Northern Blot Analysis ◽  
Hydroxysteroid Dehydrogenase ◽  
Dependent Manner ◽  
Human Trophoblast ◽  
Kinase C ◽  
Cytotrophoblastic Cell ◽  
Choriocarcinoma Cells ◽  
Human Choriocarcinoma Cells

ABSTRACT The type 2 isoform of 11 β-hydroxysteroid dehydrogenase (11β-HSD2), which catalyzes the conversion of cortisol to hormonally inactive cortisone in man, is principally expressed in the placenta and mineralocorticoid target tissues, kidney and colon. To date, few studies have addressed the regulation of this novel 11β-HSD2 isoform. We have characterized the nature and regulation of the 11β-HSD activity expressed in a human cytotrophoblastic cell line, the JEG-3 choriocarcinoma cell. The 11β-HSD activity in JEG-3 cell homogenates required NAD+ as cofactor with NADP ineffective and demonstrated a high affinity for cortisol (apparent Km 31 nm). Incubation of JEG-3 cells with forskolin and dibutyryl cyclic AMP increased 11β-HSD2 activity several-fold in a time-dependent manner, while treatment with phorbol ester had little, if any, effect on 11β-HSD2 activity. Northern blot analysis of RNA isolated from JEG-3 cells after these treatments demonstrated a marked increase in a 1·9 kb 11β-HSD2 mRNA species in cells treated with forskolin for 24 h. We conclude that 11β-HSD2 is regulated by activation of the protein kinase A pathway, but not the protein kinase C pathway in human choriocarcinoma cells, and that this regulation occurs at a pretranslational level. JEG-3 cells provide an excellent model for further studies on the regulation of 11β-HSD2 gene expression in human trophoblast tissue.

scholarly journals DNA Binding of TEA/ATTS Domain Factors Is Regulated by Protein Kinase C Phosphorylation in Human Choriocarcinoma Cells

2001 ◽  
Vol 276 (26) ◽  
pp. 23464-23470 ◽  
Author(s):  
Shi-Wen Jiang ◽  
Maoqing Dong ◽  
Miguel A. Trujillo ◽  
Laurence J. Miller ◽  
Norman L. Eberhardt
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Dna Binding ◽  
Kinase C ◽  
Choriocarcinoma Cells ◽  
Human Choriocarcinoma Cells

Abstract 458: Chronic Inhibition of Protein Kinase C Improves Coronary Endothelial Function in the Setting of Diabetes and Hypoxia

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Zhiqi Zhang ◽  
Yuhong Liu ◽  
guangbin shi ◽  
Kim Justin ◽  
Song Yi ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Substance P ◽  
Endothelial Function ◽  
Adenosine Diphosphate ◽  
Dependent Manner ◽  
Diabetic Mice ◽  
Coronary Endothelial Function ◽  
Kinase C

Background: Both Diabetes (DM) and hypoxia/re-oxygenation (H/R) upregulate protein kinase C (PKC), resulting in coronary endothelial dysfunction. We hypothesized that chronic inhibition of PKC protects coronary endothelial function against DM and H/R injury. Methods: Genetically modified obesity and type-2 diabetic mice (female) were orally treated with or without selective PKCα/β inhibitor ruboxistaurin (10μg/g) for 4 weeks (n = 6/group). Coronary small arteries (70-110 μm in diameter) were then dissected from the harvested heart of mice. The isolated vessels were subjected to 60-min of hyperkalemic cardioplegic hypoxia (15°C) and then reperfused with oxygenated Krebs-Henseleit buffer for 60 minutes. At the end of 60-min re-oxygenation, all vessels was pretreated with endothelin-1 and then the responses to endothelium-dependent vasodilators, adenosine-diphosphate (ADP) and substance P were examined. Results: PKCα/β inhibition significantly improved the recovery of coronary endothelial function in the small coronary arteries of diabetic mice showing increased relaxation response to ADP and substance P in dose-dependent manner compared with the DM control (no-pretreatment alone) (*p<0.05). Conclusion: Chronic inhibition of PKC significantly improved the recovery of coronary endothelial function against a period of cardiolpegic H/R in the diabetic microvasculature. These data suggest that the PKC inhibitor ruboxistaurin represents a novel potential therapeutic for coronary endothelial dysfunctionin patients with DM following cardioplegic ischemia and reperfusion.

Endotoxin-Induced Tissue Factor in Human Monocytes is Dependent upon Protein Kinase C Activation

1993 ◽  
Vol 70 (05) ◽  
pp. 800-806 ◽  
Author(s):  
C Ternisien ◽  
M Ramani ◽  
V Ollivier ◽  
F Khechai ◽  
T Vu ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Tissue Factor ◽  
Factor Ix ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Human Monocytes ◽  
Kinase C ◽  
Pkc Activation

SummaryTissue factor (TF) is a transmembrane receptor which, in association with factors VII and Vila, activates factor IX and X, thereby activating the coagulation protease cascades. In response to bacterial lipopolysaccharide (LPS) monocytes transcribe, synthesize and express TF on their surface. We investigated whether LPS-induced TF in human monocytes is mediated by protein kinase C (PKC) activation. The PKC agonists phorbol 12- myristate 13-acetate (PMA) and phorbol 12, 13 dibutyrate (PdBu) were both potent inducers of TF in human monocytes, whereas 4 alpha-12, 13 didecanoate (4 a-Pdd) had no such effect. Both LPS- and PMA-induced TF activity were inhibited, in a concentration dependent manner, by three different PKC inhibitors: H7, staurosporine and calphostin C. TF antigen determination confirmed that LPS-induced cell-surface TF protein levels decreased in parallel to TF functional activity under staurosporine treatment. Moreover, Northern blot analysis of total RNA from LPS- or PMA-stimulated monocytes showed a concentration-dependent decrease in TF mRNA levels in response to H7 and staurosporine. The decay rate of LPS-induced TF mRNA evaluated after the arrest of transcription by actinomycin D was not affected by the addition of staurosporine, suggesting that its inhibitory effect occurred at a transcriptional level. We conclude that LPS-induced production of TF and its mRNA by human monocytes are dependent on PKC activation.

Tamoxifen inhibits phorbol ester stimulated osteoclastic bone resorption: An effect mediated by calmodulin

2000 ◽  
Vol 78 (6) ◽  
pp. 715-723 ◽  
Author(s):  
John P Williams ◽  
Margaret A McKenna ◽  
Allyn M Thames III ◽  
Jay M McDonald
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Bone Resorption ◽  
Phorbol Ester ◽  
Phorbol Esters ◽  
Fold Increase ◽  
Dependent Manner ◽  
Osteoclast Activity ◽  
Kinase C ◽  
Protein Kinase Cα

Tamoxifen inhibits bone resorption by disrupting calmodulin-dependent processes. Since tamoxifen inhibits protein kinase C in other cells, we compared the effects of tamoxifen and the phorbol ester, phorbol myristate acetate, on osteoclast activity. Phorbol esters stimulate bone resorption and calmodulin levels four-fold (k0.5 = 0.1–0.3 µM). In contrast, tamoxifen inhibited osteoclast activity ~60% with an IC50 of 1.5 µM, had no apparent effect on protein kinase C activity in whole-cell lysates, and reduced protein kinase Cα recovered by immunoprecipitation 75%. Phorbol esters stimulated resorption in a time-dependent manner that was closely correlated with a similar-fold increase in calmodulin. Protein kinase Cα, β, δ, ε, and ζ were all down-regulated in response to phorbol ester treatment. Tamoxifen and trifluoperazine inhibited PMA-dependent increases in bone resorption and calmodulin by 85 ± 10%. Down-regulation of protein kinase C isoforms by phorbol esters suggests that the observed increases in bone resorption and calmodulin levels are most likely due to a mechanism independent of protein kinase C and dependent on calmodulin. In conclusion, the data suggest that protein kinase C negatively regulates calmodulin expression and support the hypothesis that the effects of both phorbol esters and tamoxifen on osteoclast activity is mediated by calmodulin.Key words: osteoclast, calmodulin, tamoxifen, osteoporosis, protein kinase C.

scholarly journals Post-transcriptional regulation of apolipoprotein E expression in mouse macrophages by phorbol ester

1993 ◽  
Vol 292 (1) ◽  
pp. 105-111 ◽  
Author(s):  
L Dory
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Apolipoprotein E ◽  
Phorbol Ester ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Mouse Macrophages ◽  
Apoe Expression

Phorbol ester-mediated differentiation of THP-1 cells (a human monocytic cell line) into mature macrophages is associated with a transcriptional induction of apolipoprotein E (apoE) expression [Auwerx, Deeb, Brunzell, Peng and Chait (1988) Biochemistry 27, 2651-2655]. Endotoxin, on the other hand, which may also act through activation of protein kinase C, is a potent inhibitor of apoE expression in mouse macrophages [Werb and Chin (1983) J. Biol. Chem. 258, 10642-10648]. The present experiments examine the effect of phorbol ester, an activator of protein kinase C, on the apoE expression in mouse thioglycollate-elicited peritoneal macrophages. Phorbol ester inhibits apoE expression in a specific, time- and dose-dependent manner. A 75% inhibition in the rate of apoE secretion, but not that of total protein, was observed following a 4.5 h incubation with 160 nM phorbol ester, although nearly full inhibition was obtained with 40 nM. The changes in apoE secretion were paralleled by similar changes in apoE synthesis, indicating synthesis as the primary site of action. The decreased rates of apoE synthesis are shown not to be due to increased apoE degradation. The profound inhibition of apoE synthesis was not accompanied by significant changes in apoE mRNA levels at any concentration of phorbol ester (up to 16 microM), or length of treatment (up to 24 h), suggesting a post-transcriptional locus of regulation of apoE expression. Although the early changes in apoE synthesis correlate with increased microsomal protein kinase C activity, the suppression of apoE expression persists even during conditions of nearly complete (> 95%) loss of protein kinase C activity, suggesting that the direct or indirect effect of protein kinase C on apoE expression is mediated by a stable phosphorylated protein, or that the observed effects are mediated through a protein kinase C species that is not readily downregulated by phorbol esters. The presented studies clearly demonstrate the potential importance of the translational regulation of apoE expression through the protein kinase C signal transduction pathway.

PKC-lambda is the atypical protein kinase C isoform expressed by immature ventricle

1997 ◽  
Vol 272 (4) ◽  
pp. H1636-H1642
Author(s):  
V. O. Rybin ◽  
P. M. Buttrick ◽  
S. F. Steinberg
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Northern Blot ◽  
Blot Analysis ◽  
Northern Blot Analysis ◽  
Ventricular Myocardium ◽  
Adult Rat ◽  
Atypical Pkc ◽  
Kinase C ◽  
Pkc Zeta

We recently identified a developmental decline in protein kinase C (PKC) isoform expression, at the level of the protein, in rat ventricular myocardium. To investigate mechanisms regulating PKC isoform expression in cardiac tissue, this study uses Northern blot analysis to compare the abundance of PKC isoform mRNAs in neonatal and adult rat ventricular myocardium. PKC-epsilon protein and mRNA were detected in both neonatal and adult rat ventricular myocardial preparations. In contrast, coordinate postnatal declines in the abundance of PKC-alpha and PKC-delta proteins and transcripts were identified. An antiserum raised against the COOH-terminal sequence of PKC-zeta detected abundant immunoreactivity in neonatal, but not adult, ventricular myocytes. However, PKC-zeta transcripts were not detectable in the heart either by Northern blot analysis or a reverse transcriptase-polymerase chain reaction approach, indicating that neither the myocytes nor the contaminating cellular elements in the heart express PKC-zeta. Rather, PKC-lambda, another atypical PKC isoform that is structurally highly homologous to PKC-zeta, was detected at the protein and mRNA level in neonatal, but not adult, ventricular myocardium. Taken together, these results establish that developmental declines in calcium-sensitive, novel, and atypical PKC isoforms are paralleled by changes in the levels of the mRNAs encoding these proteins, suggesting transcriptional regulation of PKC during normal cardiac development. The results of this study further identify PKC-lambda as the atypical PKC isoform expressed by the immature ventricle.

Protein kinase C-ζ modulates thromboxane A2-mediated apoptosis in adult ventricular myocytes via Akt

2002 ◽  
Vol 282 (1) ◽  
pp. H320-H327 ◽  
Author(s):  
Yukitaka Shizukuda ◽  
Peter M. Buttrick
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cardiac Myocytes ◽  
Ventricular Myocytes ◽  
Kinase Assay ◽  
Dependent Manner ◽  
Adult Rat ◽  
Kinase C ◽  
Adult Cardiac Myocytes ◽  
Pkc Ζ

We hypothesized that thromboxane A2 (TxA2) receptor stimulation directly induces apoptosis in adult cardiac myocytes. To investigate this, we exposed cultured adult rat ventricular myocytes (ARVM) to a TxA2 mimetic [1S-[1α,2α(Z),3β(1E,3S*),4α]]-7-[3-[3-hydroxy-4-(4-iodophenoxy)-1-butenyl]-7-oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid (I-BOP) for 24 h. Stimulation with I-BOP induced apoptosis in a dose-dependent manner and was completely prevented by a TxA2 receptor antagonist, SQ-29548. We further investigated the role of protein kinase C (PKC) in this process. TxA2 stimulation resulted in membrane translocation of PKC-ζ but not PKC-α, -βII, -δ, and -ε at 3 min and 1 h. The activation of PKC-ζ by I-BOP was confirmed using an immune complex kinase assay. Treatment of ARVM with a cell-permeable PKC-ζ pseudosubstrate peptide (ζ-PS) significantly attenuated apoptosis by I-BOP. In addition, I-BOP treatment decreased baseline Akt activity and its decrease was reversed by treatment with ζ-PS. The inhibition of phosphatidylinositol 3-kinase upstream of Akt by wortmannin or LY-294002 abolished the antiapoptotic effect of ζ-PS. Therefore, our results suggest that the activation of PKC-ζ modulates TxA2 receptor-mediated apoptosis at least, in part, through Akt activity in adult cardiac myocytes.

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