scholarly journals Endothelin-1 stimulates cytosolic phospholipase A2 activity and gene expression in rat glomerular mesangial cells

1994 ◽  
Vol 46 (6) ◽  
pp. 1644-1652 ◽  
Author(s):  
Herbert Schramek ◽  
Yizheng Wang ◽  
Martha Konieczkowski ◽  
Michael S. Simonson ◽  
Michael J. Dunn
Keyword(s):  
Gene Expression ◽  
Phospholipase A2 ◽  
Mesangial Cells ◽  
Cytosolic Phospholipase A2 ◽  
Glomerular Mesangial Cells ◽  
Endothelin 1 ◽  
Cytosolic Phospholipase ◽  
Phospholipase A2 Activity

scholarly journals Cytosolic phospholipase A2 gene expression in rat mesangial cells is regulated post-transcriptionally

1994 ◽  
Vol 304 (2) ◽  
pp. 417-422 ◽  
Author(s):  
A Tay ◽  
P Maxwell ◽  
Z G Li ◽  
H Goldberg ◽  
K Skorecki
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Phospholipase A2 ◽  
Mesangial Cells ◽  
Luciferase Activity ◽  
Cytosolic Phospholipase A2 ◽  
Mrna Levels ◽  
Glomerular Mesangial Cells ◽  
Coding Region ◽  
Cytosolic Phospholipase

Cytosolic phospholipase A2 (cPLA2) is thought to be the rate-limiting enzyme in the arachidonic acid/eicosanoid cascade. The ability of various agonists to increase steady-state cPLA2 mRNA levels has previously been reported. The current study delineates the contributions of transcriptional and post-transcriptional processes to the regulation of cPLA2 gene expression in response to a variety of agonists in cultured rat glomerular mesangial cells. Epidermal growth factor, platelet-derived growth factor, serum and phorbol myristate acetate all increase the half-life of cPLA2 mRNA transcripts, indicating a role for post-transcriptional modulation of gene expression. The presence of three ATTTA motifs in the 3′ untranslated region (3′UTR) of the rat cPLA2 cDNA is ascertained. Heterologous expression of chimeric constructs with different 3′UTRs ligated into the 3′ end of the luciferase coding region reveals that the presence of the cPLA2 3′UTR results in reduced luciferase activity compared with constructs without the cPLA2 3′UTR. Furthermore, the luciferase activity in the constructs with the cPLA2 3′UTR is increased in response to the same agonists which stabilize endogenous cPLA2 mRNA. A negligible effect of these agonists on transcriptional control of cPLA2 is evident using promoter-reporter constructs expressed in transient and stable transfectants. Taken together, these results indicate predominant post-transcriptional regulation of cPLA2 mRNA levels.

scholarly journals Enhancement of Cortisol-Induced 11β-Hydroxysteroid dehydrogenase Type 1 Expression by Interleukin 1β in Cultured Human Chorionic Trophoblast Cells

Endocrinology ◽  
2006 ◽  
Vol 147 (5) ◽  
pp. 2490-2495 ◽  
Author(s):  
Wenjiao Li ◽  
Lu Gao ◽  
Yan Wang ◽  
Tao Duan ◽  
Leslie Myatt ◽  
...  
Keyword(s):  
Gene Expression ◽  
Phospholipase A2 ◽  
Mrna Expression ◽  
Reporter Gene ◽  
Reductase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Cytosolic Phospholipase A2 ◽  
Trophoblast Cells ◽  
Cytosolic Phospholipase

Chorion is the most abundant site of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) expression within intrauterine tissues. It is important to study the regulation of 11β-HSD1 expression in the chorion in terms of local cortisol production during pregnancy. Using real-time PCR and enzyme activity assay, we found that cortisol (1 μm) and IL-1β (10 ng/ml) for 24 h significantly increased 11β-HSD1 mRNA expression and reductase activity in cultured human chorionic trophoblasts. A further significant increase of 11β-HSD1 mRNA expression and reductase activity was observed with cotreatment of cortisol and IL-1β. To explore the mechanism of induction, 11β-HSD1 promoter was cloned into pGL3 plasmid expressing a luciferase reporter gene. By transfecting the constructed vector into WISH cells, an amnion-derived cell line, we found that cortisol (1 μm) or IL-1β (10 ng/ml) significantly increased reporter gene expression. Likewise, an additional increase in reporter gene expression was observed with cotreatment of cortisol and IL-β. To explore the physiological significance of 11β-HSD1 induction in the chorion, we studied the effect of cortisol on cytosolic phospholipase A2 and cyclooxygenase 2 expression. We found that treatment of chorionic trophoblast cells with cortisol (1 μm) induced both cytosolic phospholipase A2 and cyclooxygenase 2 mRNA expression. We conclude that cortisol up-regulates 11β-HSD1 expression through induction of promoter activity, and the effect was enhanced by IL-1β, suggesting that more biologically active glucocorticoids could be generated in the fetal membranes in the presence of infection, which may consequently feed forward in up-regulation of prostaglandin synthesis.

scholarly journals Characterization of phospholipase A2 in monocytic cell lines. Functional and biochemical aspects of membrane association

1991 ◽  
Vol 276 (3) ◽  
pp. 631-636 ◽  
Author(s):  
W Rehfeldt ◽  
R Hass ◽  
M Goppelt-Struebe
Keyword(s):  
Substrate Specificity ◽  
Phospholipase A2 ◽  
Cell Lines ◽  
Cytosolic Phospholipase A2 ◽  
Biologically Active ◽  
Ph Optimum ◽  
Monocytic Cell ◽  
Cytosolic Phospholipase ◽  
Membrane Bound ◽  
Phospholipase A2 Activity

Phospholipase A2 activity was characterized in the human monocytic tumour-cell lines U937 and THP1. The enzyme showed an alkaline pH optimum and substrate specificity for arachidonoyl-phosphatidylcholine. The activation of phospholipase A2 required bivalent cations (Ca2+ greater than Mg2+ = Sr2+ greater than Ba2+). Investigation of the subcellular distribution of the enzyme revealed that the phospholipase A2 activity was shifted to the cytosol in the presence of EDTA, indicating that the association of the enzyme with the cellular membranes is Ca2+ (bivalent-cation)-dependent. Stimulation of THP1 cells for 2-4 h with the phorbol ester phorbol 12-myristate 13-acetate (PMA) activated cytosolic and membrane-bound phospholipase A2. At this time, no effect of PMA on phospholipase A2 activity was observed in the less mature U937 cells. However, when both cell lines were induced to differentiate along the monocytic pathway by a 2-3-day treatment with PMA, the cells released significant amounts of arachidonic acid and prostanoids. Compared with undifferentiated control cells, these PMA-differentiated cells showed a decrease in cytosolic phospholipase A2 activity and an increase in membrane-bound activity. Membrane-bound and cytosolic enzyme showed the same pH optimum, Ca(2+)-dependency and substrate specificity. These data indicate that membrane-bound and cytosolic phospholipase A2 activities represent one enzyme and that the membrane-bound form is the biologically active phospholipase A2.

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