15-hydroxy-11-alpha-9-alpha-(epoxymethano)prosta-5-13-dienoic-acid and carboprostacyclin

To determine whether prostanoids, nonsteroidal anti-inflammatory drugs (NSAIDs), and members of the tumor necrosis factor superfamily can regulate placental secretion of interleukin-6 (IL-6) and whether labor influences any such effects.. Villous fragments of term, human placenta were kept in culture for up to 4 hours, and IL-6 concentrations were measured in the supernatant. We assessed the effects of the following prostanoids: PGE(2), PGF(2alpha), thromboxane A(2) mimetic (U-46619), and carbacyclin, a stable prostacyclin analogue (all at 1 microM); NSAIDs: indomethacin (150 microM) or nimesulide (100 microM); and Fas ligand (5 ng/mL).. Secretion (mean +/- standard error) of IL-6 was, for control conditions, 1.92 +/- 0.28 fmol/mg wet weight per 3 hours; for PGE(2), 3.57 +/- 0.29 fmol/mg wet weight per 3 hours, P <.01; and for carbacyclin, 3.11 +/- 0.44 fmol/mg wet weight per 3 hours, P <.01. Incubation with PGF(2alpha) or the thromboxane A(2) analogue, U46619, had no effect on IL-6 secretion under these conditions. Fas ligand stimulated IL-6 secretion (3.06 +/- 0.38 fmol/mg wet weight per 3 hours, P <.05). Labor did not alter the effects of prostanoids or FasL. The effects of NSAIDs were assessed over 4 hours. Secretion (median, interquartile range) was, under control conditions 3.26, 2.83-6.23 fmol/mg wet weight per 4 hours, with indomethacin 1.4, 1.28-3.21 (P <.05), and with nimesulide 0.75, 0.50-1.56 fmol/mg wet weight per 4 hours. The magnitude of the effect of Fas ligand in the presence of NSAIDs depended on whether the placentas were delivered before or after labor.. Prostanoids, NSAIDs, and the Fas ligand regulate placental IL-6 secretion. Although the effects of individual agents did not vary with the presence or absence of labor, modulation of IL-6 secretion by labor became apparent when agents were combined.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Anti-Inflammatory Agents, Non-Steroidal; Dinoprost; Dinoprostone; Drug Interactions; Epoprostenol; Fas Ligand Protein; Female; Humans; Interleukin-6; Labor, Obstetric; Membrane Glycoproteins; Models, Biological; Placenta; Pregnancy; Prostaglandins; Thromboxane A2; Tumor Necrosis Factor-alpha

Using simultaneous whole-cell patch-clamp and fluorescence measurements of [Ca2+]i in rat megakaryocytes we have investigated the requirement for functional inositol 1,4,5-trisphosphate (IP3) receptors in Ca2+ release induced by membrane depolarization during agonist stimulation. Voltage-dependent Ca2+ release was observed during application of the IP3-generating agonists U46619 (a thromboxane A2 analogue) and ADP. Furthermore, voltage-dependent Ca2+ release was observed in the absence of exogenous agonist following sensitization of IP3 receptors with thimerosal. Depolarization-induced Ca2+ release was not detected during depletion of intracellular Ca2+ stores by thapsigargin. Thus, depletion of stores alone is not sufficient to confer voltage dependence upon the Ca2+ release mechanism. Block of IP3 receptors by carbacyclin-stimulated elevations in cAMP, uncaging of cAMP or exposure to a high concentration of caffeine reversibly abolished Ca2+ increases stimulated by both ADP and depolarization. The cAMP-dependent block was prevented by a peptide inhibitor of protein kinase A, indicating that an alteration of adenylate cyclase activity leading to modulation of protein kinase A activity does not underlie the control of Ca2+ release by voltage. These results are consistent with the requirement for functional IP3 receptors for voltage control of Ca2+ release from intracellular stores during inositol lipid signalling. The data also indicate the involvement of a voltage sensor downstream of surface membrane receptors in the depolarization-evoked Ca2+ response.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Adenosine Diphosphate; Animals; Anti-Infective Agents, Local; Caffeine; Calcium; Calcium Channels; Calcium Signaling; Enzyme Inhibitors; Epoprostenol; Inositol 1,4,5-Trisphosphate Receptors; Male; Megakaryocytes; Patch-Clamp Techniques; Phosphodiesterase Inhibitors; Platelet Aggregation Inhibitors; Rats; Rats, Wistar; Receptors, Cytoplasmic and Nuclear; Thapsigargin; Thimerosal; Vasoconstrictor Agents

Prostaglandin endoperoxide H synthases and their arachidonate products have been implicated in modulating angiogenesis during tumor growth and chronic inflammation. Here we report the involvement of thromboxane A(2), a downstream metabolite of prostaglandin H synthase, in angiogenesis. A TXA(2) mimetic, U46619, stimulated endothelial cell migration. Angiogenic basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF) increased TXA(2) synthesis in endothelial cells three- to fivefold. Inhibition of TXA(2) synthesis with furegrelate or CI reduced HUVEC migration stimulated by VEGF or bFGF. A TXA(2) receptor antagonist, SQ29,548, inhibited VEGF- or bFGF-stimulated endothelial cell migration. In vivo, CI inhibited bFGF-induced angiogenesis. Finally, development of lung metastasis in C57Bl/6J mice intravenously injected with Lewis lung carcinoma or B16a cells was significantly inhibited by thromboxane synthase inhibitors, CI or furegrelate sodium. Our data demonstrate the involvement of TXA(2) in angiogenesis and development of tumor metastasis.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Benzofurans; Bridged Bicyclo Compounds, Heterocyclic; Chemotaxis; Dinoprost; Dinoprostone; Endothelial Growth Factors; Endothelium, Vascular; Enzyme Inhibitors; Epoprostenol; Fatty Acids, Unsaturated; Fibroblast Growth Factor 2; Humans; Hydrazines; Lung Neoplasms; Lymphokines; Male; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Neovascularization, Pathologic; Rats; Receptors, Thromboxane; Thromboxane A2; Thromboxane-A Synthase; Umbilical Veins; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

This study investigates whether phorbol esters increase phosphoinositide hydrolysis in intact vascular smooth muscle, and the mechanism underlying the hydrolysis. Phorbol myristate acetate induced time- and concentration-dependent increases in phosphoinositide hydrolysis, as demonstrated by elevated inositol monophosphate levels, in deendothelialized rat aorta. The phorbol ester-elevated inositol monophosphate levels were abolished by indomethacin, a cyclooxygenase inhibitor, but were only partially decreased by SQ29548, a thromboxane A2/prostaglandin H2 receptor antagonist. SQ29548 also only partially decreased elevated inositol monophosphate levels due to prostaglandin E2, prostaglandin F2alpha, prostaglandin I2 and carbacyclin, a stable prostaglandin I2 analog. SQ29548 abolished elevated inositol monophosphate levels due to U46619, a stable thromboxane A2/prostaglandin H2 receptor agonist. These studies demonstrate that phorbol esters increase phosphoinositide hydrolysis in intact vascular smooth muscle, and that the increase is due, at lease in part, to endogenously released prostaglandins other than prostaglandin H2.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Aorta, Thoracic; Bridged Bicyclo Compounds, Heterocyclic; Epoprostenol; Fatty Acids, Unsaturated; Hydrazines; Hydrolysis; Indomethacin; Inositol Phosphates; Muscle, Smooth, Vascular; Phosphatidylinositols; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Rats; Rats, Sprague-Dawley; Signal Transduction; Tetradecanoylphorbol Acetate

This study was conducted to determine if high perinatal prostaglandin (PG) and thromboxane (TxA2) levels modified their choroidal vasomotor effects and receptor levels. Both nonperfused (eyecup preparations) and perfused choroidal vessels from saline- or ibuprofen-treated 1-day-old pigs and tissues from adult pigs were used; all prostanoids produced similar vasomotor effects on both preparations. Choroidal PGF2alpha, TxA2, PGI2, and PGD2 levels were higher in the newborn than in adult pigs; injections of ibuprofen (40 mg/kg every 4 h for 48 h) into newborn pigs significantly decreased choroidal levels of all these prostanoids. PGF2alpha and the TxA2 mimetic U-46619 caused less choroidal vasoconstriction and production of inositol 1,4,5-trisphosphate (IP3) in the newborn than in adult pigs. Ibuprofen treatment increased choroidal PGF2alpha vasoconstrictor effects, IP3 production, and receptors, but did not modify response to U-46619. Carbaprostacyclin (PGI2 analog) caused a greater choroidal vasodilatation and adenosine adenosine 3',5'-cyclic monophosphate (cAMP) production in the newborn than in adult pigs; these effects were not modified by ibuprofen. PGD2 did not increase cAMP but caused greater dilatation and nitrite [oxidation product of nitric oxide (NO)] production in the choroid of newborn than of adult pigs, which were decreased to adult levels by ibuprofen and the NO synthase inhibitor N(omega)-nitro-L-arginine. These data suggest that high perinatal PG levels downregulate PGF2alpha receptors and vascular effects but do not modify choroidal responses to TxA2 and PGI2; NO seems to contribute to the vasodilator effects of PGD2.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Aging; Animals; Animals, Newborn; Choroid; Cyclic AMP; Cyclic GMP; Dinoprost; Down-Regulation; Epoprostenol; Ibuprofen; Inositol 1,4,5-Trisphosphate; Nitric Oxide; Nitroarginine; Prostaglandin D2; Prostaglandin Endoperoxides, Synthetic; Prostaglandins; Prostaglandins, Synthetic; Receptors, Prostaglandin; Swine; Thromboxane A2; Vasoconstrictor Agents; Vasodilation

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Arachidonic Acid; Blood Platelets; Chromatography, High Pressure Liquid; Collagen; Epoprostenol; Glutathione Transferase; GTP-Binding Proteins; Humans; Kinetics; Leukotriene C4; Platelet Membrane Glycoproteins; Prostaglandin Endoperoxides, Synthetic; Protein Kinase C; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Receptors, Thrombin; Receptors, Thromboxane; Tetradecanoylphorbol Acetate; Thrombin; Thromboxane A2; Type C Phospholipases

Prostaglandin (PG) I2 elicits a biphasic concentration-response curve in rat aorta: lower concentrations elicit relaxation, whereas at higher concentrations, the relaxation is reversed. The purpose of this study was to investigate 1) the nature of the receptors that mediate these effects and 2) whether the relaxant efficacy of PGI2 is decreased at higher PGI2 concentrations by PGI2-induced contraction. PGI2 (1 microM), the stable PGI2 analogue carbacyclin (1 microM), and PGE1 (3 microM) induced maximal relaxations of 55, 40, and 63%, respectively, of norepinephrine-contracted aorta, whereas higher concentrations of PGI2, carbacyclin, and PGE1 reversed the relaxation. The thromboxane (Tx) A2-PGH2 receptor antagonist, SQ-29548, abolished the reversal of the PGI2-, carbacyclin-, and PGE1-induced relaxation, and maximal relaxations to PGI2, carbacyclin, and PGE1 increased to 73, 85, and 89% of the norepinephrine contraction, respectively, with 50% effective concentrations of 0.16, 0.43, and 0.83 microM, respectively. PGE2 and PGD2 did not induce relaxation in the presence or absence of SQ-29548. PGI2 and carbacyclin displaced the TxA2-PGH2 receptor ligand 1S-[1 alpha,2 beta(5Z),3 alpha(1E,3S),4 alpha]-7-(3-[3-hydroxy-4-(p- [125I]iodophenoxy)-1-butenyl]7-oxabicyclo[2.2.1]hept-2-yl]-5- heptenoic acid from cultured rat aorta smooth muscle cells with concentrations of competing ligand that displaced 50% of the specifically bound radioligand from its binding site of 6.0 and 2.3 microM, respectively. These results suggest that 1) PGI2 induces relaxation through a PGI2-PGE1 receptor, and 2) higher concentrations of PGI2 act at the TxA2-PGH2 receptor to decrease PGI2-induced relaxation.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Bridged Bicyclo Compounds; Bridged Bicyclo Compounds, Heterocyclic; Cells, Cultured; Epoprostenol; Fatty Acids, Unsaturated; Hydrazines; Male; Muscle, Smooth, Vascular; Prostaglandin Endoperoxides, Synthetic; Prostaglandins; Rats; Rats, Sprague-Dawley; Receptors, Thromboxane; Thromboxane A2; Vasoconstriction; Vasoconstrictor Agents; Vasomotor System

FTIR spectra measurements and full optimization curve analysis of their spectra were done to obtain parameters of the OH and C = O stretching vibration bands for intramolecular hydrogen bondings in thromboxane (TX)A2 receptor partial agonist (CTA2), prostaglandin (PG)E2, PGD2, PGF2 alpha, prostacyclin (PGI2) receptor agonist (carbacyclin), and their related compounds in dilute CCl4 solutions. For CTA2, PGE2, PGD2, and PGF2 alpha, cyclic intramolecular hydrogen bonds involving a 15-membered ring similar to that observed for the TXA2 receptor agonist (U-46619) were found between a carboxyl group of the alpha-side chain and a 15-hydroxyl group of the omega-side chain. The arrangement of these side chains was P-shaped, and the percentage of the intramolecular hydrogen-bonded molecules with the 15-membered ring in CCl4 solution showed a high value of ca. 80% for these compounds. In addition, it was found that the cyclic intramolecular hydrogen bonds involving the 13-, 12-, and 12-membered rings in PGE2, PGD2, and PGF2 alpha, respectively, are formed between the carboxyl group of the alpha-side chain and the 11-, 9-, and 9-hydroxyl groups of a cyclopentane ring, respectively, although the percentages of the intramolecular hydrogen-bonded molecules with these membered rings are very small. It was also found that the hydrogen bond is more easily formed in the order of the 11-, 9-, and 15-hydroxyl groups. For carbacyclin, the cyclic intramolecular hydrogen bond involving the 13-membered ring was found between the carboxyl group of the alpha-side chain and the 11-hydroxyl group. The percentage of the intramolecular hydrogen-bonded molecules showed the value of 58% for carbacyclin. On the basis of information on the side-chain conformations in CCl4, we examined the structure-activity relationships for U-46619 in place of TXA2, PGE2, PGD2, PGF2 alpha, and carbacyclin in place of PGI2.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Bridged Bicyclo Compounds; Carbon Tetrachloride; Dinoprost; Dinoprostone; Dogs; Epoprostenol; Fatty Acids, Monounsaturated; Hydrogen Bonding; Macromolecular Substances; Models, Molecular; Molecular Structure; Prostaglandin D2; Prostaglandin Endoperoxides, Synthetic; Receptors, Thromboxane; Solutions; Spectroscopy, Fourier Transform Infrared; Structure-Activity Relationship; Thromboxane A2

We examined the influence of stable prostacyclin analogues (carbacyclin) and thromboxane A2 (U46619) on atherosclerotic properties of cells: [3H]thymidine incorporation and intracellular cholesterol content. A primary culture of human aortic subendothelial cells derived from atherosclerotic plaques was used. Carbacyclin exerted a direct anti-atherosclerotic effect, significantly reducing atherosclerotic manifestations of cells, while agent U46619 stimulated proliferation and cholesterol accumulation, i.e. demonstrated atherogenic potency in culture. Calcium antagonists (verapamil and diltiazem) markedly enhanced anti-atherosclerotic properties of carbacyclin and restricted the atherogenicity of U46619.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Aorta; Arteriosclerosis; Cells, Cultured; Diltiazem; DNA Replication; Epoprostenol; Humans; Muscle, Smooth, Vascular; Prostaglandin Endoperoxides, Synthetic; Prostaglandins, Synthetic; Verapamil

We investigated the effects of stable analogues of prostacyclin (carbacyclin) and thromboxane A2 (U46619) and various calcium antagonists on atherosclerotic cellular indices, intracellular cholesterol content and [3H]thymidine incorporation. Primary culture of human subendothelial cells derived from atherosclerotic plaques of aorta was used. Carbacyclin reduced cholesterol accumulation and cell proliferation. U46619 in opposite to carbacyclin stimulated this processes. In general, carbacyclin exerted a direct antiatherosclerotic and U46619 - atherogenic action in culture. Calcium antagonists: dihydropyridines, verapamil derivatives and diltiazem demonstrated antiatherosclerotic properties themselves and potentiated carbacyclin effect but restricted atherogenicity of U46619.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Aorta; Arteriosclerosis; Calcium Channel Blockers; Cells, Cultured; Cholesterol; DNA Replication; Epoprostenol; Humans; Muscle, Smooth, Vascular; Prostaglandin Endoperoxides, Synthetic

The effect of prostacyclin and stable thromboxane analog A2 on endothelial culture of human aorta was studied. It was shown that prostacyclin inhibited accumulation of cholesterol in the cells and their proliferation, while thromboxane exhibited an opposite effect. Calcium antagonists potentiated effects of prostacyclin and inhibited them in respect to thromboxane. Screening of a number of synthetic agents affecting arachidonic acid metabolism was carried out. It was found that lipoxygenase inhibitors suppress cholesterol accumulation and proliferation in cells presumably due to enhancement of prostacyclin synthesis and inhibition of leukotriene formation. The balance between various eicosanoids is supposed to be an important factor of atherogenesis regulation, while antiatherogenic effect of calcium antagonists is somehow associated with the impact of eicosanoids on atherogenesis regulation.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Adult; Aorta; Calcium Channel Blockers; Cell Division; Cholesterol; Epoprostenol; Humans; In Vitro Techniques; Lipoxygenase Inhibitors; Male; Middle Aged; Prostaglandin Endoperoxides, Synthetic

The influence of stable analogues of prostacyclin (carbacyclin) and thromboxane A2 (U46619), as well as lipoxygenase inhibitors, on the lipid metabolism of cells cultured from atherosclerotic intima of human aorta was analyzed. Carbacyclin and at concentrations of 200 ng/ml during 24 hours of incubation caused a 2-fold decrease in the level of cholesteryl esters and triglycerides in cells obtained from atherosclerotic lesion. Phospholipid and free cholesterol content did not change during the same period. Carbacylin decreased incorporation of [14C]oleate into intracellular neutral lipids. U46619 produced intracellular lipid accumulation. U46619 stimulated uptake [14C]oleate into triglycerides and cholesteryl esters. Two lipoxygenase inhibitors possessed "antiatherosclerotic" activity in primary culture significantly reducing cholesteryl ester content of cells isolated from atherosclerotic lesions.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Aorta; Cells, Cultured; Cholesterol; Cholesterol Esters; Epoprostenol; Humans; Lipid Metabolism; Lipoxygenase Inhibitors; Muscle, Smooth, Vascular; Phospholipids; Prostaglandin Endoperoxides, Synthetic; Prostaglandins, Synthetic; Triglycerides