Differential stimulation of PGE2 synthesis in mesangial cells by angiotensin and A23187

1985 ◽  
Vol 248 (1) ◽  
pp. C119-C126 ◽  
Author(s):  
D. Schlondorff ◽  
J. Perez ◽  
J. A. Satriano
Keyword(s):  
Arachidonic Acid ◽  
Angiotensin Ii ◽  
Mesangial Cells ◽  
Ionophore A23187 ◽  
Arachidonic Acid Release ◽  
Tight Coupling ◽  
Pge2 Synthesis ◽  
Maximal Stimulation ◽  
Acid Release ◽  
Stimulation Of

The mechanism of arachidonic acid release and prostaglandin E2 (PGE2) synthesis was studied in cultured mesangial cells from rat kidneys. Both the ionophore A23187 and angiotensin II stimulated radioimmunoassayable PGE2 synthesis. The effect of angiotensin occurred within minutes, with half-maximal stimulation around 10(-9) M. In cells prelabeled with [14C]arachidonate, A23187 caused release of [14C]-arachidonate from all phospholipids. In contrast, angiotensin II caused preferential release of [14C]arachidonate from phosphatidylinositol, associated with a significant increase in 14C-labeled phosphatidic acid, mono- and diacylglyceride, and arachidonate. These results indicate that angiotensin preferentially, but not exclusively, stimulates a phosphatidylinositol-specific phospholipase C, whereas A23187 results in unspecific stimulation of phospholipases. The tight coupling between an angiotensin-responsive phospholipid-arachidonate pool and cyclooxygenase may be responsible for the specificity of the response to angiotensin.

scholarly journals Possible regulatory functions of protein kinase C-α and -ε isoenzymes in rat renal mesangial cells. Stimulation of prostaglandin synthesis and feedback inhibition of angiotensin II-stimulated phosphoinositide hydrolysis

1991 ◽  
Vol 279 (2) ◽  
pp. 441-445 ◽  
Author(s):  
A Huwiler ◽  
D Fabbro ◽  
J Pfeilschifter
Keyword(s):  
Arachidonic Acid ◽  
Angiotensin Ii ◽  
Mesangial Cells ◽  
Feedback Inhibition ◽  
Term Treatment ◽  
Arachidonic Acid Release ◽  
Kinase C ◽  
Pkc Epsilon ◽  
Acid Release ◽  
Pkc Alpha

Short-term treatment of mesangial cells with phorbol 12-myristate 13-acetate (PMA) decreases angiotensin II-induced InsP3 formation, but potentiates hormone-stimulated arachidonic acid release and prostaglandin (PG) E2 synthesis. Long-term treatment with PMA augments hormone-stimulated InsP3 generation (after 8 h treatment), but eliminates angiotensin II-induced arachidonic acid release and PGE2 formation (after 24 h treatment). By using specific antibodies it is observed that mesangial cells express two protein kinase C (PKC) isoenzymes, PKC-alpha and -epsilon. No PKC-beta and -gamma isoenzymes are detected. On exposure to PMA a complete depletion of PKC-alpha is observed within 8 h. In contrast, down-regulation of PKC-epsilon to 10-20% of that found in control cells requires a 24 h treatment with PMA. These results may imply that PKC-alpha mediates feedback inhibition of phosphoinositide hydrolysis, whereas PKC-epsilon is a candidate for regulating PG synthesis in mesangial cells.

ERK and p38 MAP kinase are involved in arachidonic acid release induced by H2O2 and PDGF in mesangial cells

2002 ◽  
Vol 282 (3) ◽  
pp. F485-F491 ◽  
Author(s):  
Misako Hayama ◽  
Risa Inoue ◽  
Satoshi Akiba ◽  
Takashi Sato
Keyword(s):  
Arachidonic Acid ◽  
Map Kinase ◽  
Mesangial Cells ◽  
P38 Map Kinase ◽  
Arachidonic Acid Release ◽  
Cytosolic Phospholipase ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Acid Release ◽  
Map Kinase Pathways

Increased prostaglandin production is implicated in the pathogenesis of glomerular disease. With this consideration, we examined the combined effects of reactive oxygen species and platelet-derived growth factor (PDGF), which might initiate glomerular dysfunction, on arachidonic acid release and cytosolic phospholipase A2 (cPLA2) activation in rat mesangial cells. H2O2-induced release of arachidonic acid was enhanced by PDGF, which by itself had little effect on the release, and the enhancement was completely inhibited by a cPLA2 inhibitor. The phosphorylation of cPLA2, extracellular signal-regulated kinase (ERK), and p38 mitogen-activated protein (MAP) kinase was upregulated by H2O2 or PDGF alone and except for ERK was enhanced further by the two in combination. The release of arachidonic acid induced by PDGF together with H2O2 was inhibited partially by an inhibitor of ERK or p38 MAP kinase and completely when the two inhibitors were combined; the inhibitory pattern was similar to that for the phosphorylation of cPLA2. These results suggest that the ERK and p38 MAP kinase pathways are involved in the increase in cPLA2activation and arachidonic acid release induced by PDGF together with H2O2.

Reduced prostacyclin formation after reoxygenation of anoxic endothelium

1990 ◽  
Vol 259 (5) ◽  
pp. C738-C745 ◽  
Author(s):  
S. L. Hempel ◽  
D. L. Haycraft ◽  
J. C. Hoak ◽  
A. A. Spector
Keyword(s):  
Arachidonic Acid ◽  
Umbilical Vein ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
High Rate ◽  
Ionophore A23187 ◽  
Arachidonic Acid Release ◽  
Cyclooxygenase Activity ◽  
Platelet Adherence ◽  
Acid Release

Human umbilical vein endothelial cells subjected to 24 h of anoxia followed by reoxygenation released less prostacyclin (PGI2) in response to thrombin, calcium ionophore A23187, or arachidonic acid. This was associated with a substantial increase in stimulated platelet adherence. Increased lactate dehydrogenase and 51Cr release occurred after 1 h of reoxygenation, but the high rate of release did not persist during the subsequent 23 h of reoxygenation. The changes in platelet adherence and PGI2 release partially resolved over 24 h. PGI2 formation from prostaglandin H2 was not reduced, suggesting that cyclooxygenase activity, but not prostacyclin synthase, is affected by reoxygenation. A decrease in arachidonic acid release from cellular lipids also occurred. The reduction in cyclooxygenase activity, but not arachidonic acid release, was prevented by the presence of ibuprofen during reoxygenation. Addition of catalase or superoxide dismutase during reoxygenation increased PGI2 release but did not completely overcome the reduction relative to control cultures. These findings suggest that the increase in platelet adherence during reoxygenation may be mediated in part by a change in cyclooxygenase activity. This is only partly overcome by extracellular oxygen species scavengers but is prevented by the presence of a reversible cyclooxygenase inhibitor during reoxygenation.

scholarly journals Loss of prostaglandin E2 release from immortalized urothelial cells obtained from interstitial cystitis patient bladders

2008 ◽  
Vol 294 (5) ◽  
pp. F1129-F1135 ◽  
Author(s):  
Prerna Rastogi ◽  
Alice Rickard ◽  
Nikolay Dorokhov ◽  
David J. Klumpp ◽  
Jane McHowat
Keyword(s):  
Arachidonic Acid ◽  
Interstitial Cystitis ◽  
Prostaglandin E ◽  
Arachidonic Acid Release ◽  
Urothelial Cells ◽  
Cell Numbers ◽  
Interstitial Cystitis Patient ◽  
Acid Release ◽  
Increased Susceptibility ◽  
Stimulation Of

Interstitial cystitis (IC) is associated with increased activated mast cell numbers in the bladder and impairment of the barrier function of the urothelium. We stimulated immortalized urothelial cells derived from the inflamed region of IC bladders (SR22A or SM28 abn) or from healthy bladders (PD07i or PD08i) with tryptase and measured phospholipase A2 (PLA2) activity and the resultant release of arachidonic acid and prostaglandin E2 (PGE2). Tryptase stimulation of either PD07i or SR22A resulted in similar increases in PLA2 activity and arachidonic acid release. However, tryptase stimulation of SR22A and SM28 abn did not result in a significant increase in PGE2 release compared with the increase in PGE2 release from tryptase-stimulated PD07i and PD08i cells. Expression of mRNA for cyclooxygenase-2 and PGE synthase was lower and mRNA for 15-hydroxyprostaglandin dehydrogenase was higher in SR22A compared with PD07i, suggesting that both decreased synthesis and increased metabolism are responsible for the lack of a PGE2 response in tryptase-stimulated SR22A cells. Since PGE2 is a cytoprotective eicosanoid, the failure to produce this metabolite in cells isolated from the IC bladder may represent an increased susceptibility to damage by proinfammatory stimuli.

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