prostaglandin-d2 and diethyl-maleate

Nrf2 is a key transcription factor that modulates cell defense mechanisms against endogenous and exogenous stress. Previously, we reported that thrombin increased matrix metalloproteinases and prostaglandin synthesis in human amnion mesenchymal cells.. We sought to determine whether activation of Nrf2 alters the effect of thrombin on prostaglandin synthesis, protease activation, and cytokine release in human amnion. Furthermore, we analyzed the effect of Nrf2 activation on thrombin-induced preterm labor in mice.. Primary human amnion mesenchymal cells and pregnant mice were employed to investigate the effect of Nrf2 on thrombin-induced inflammation and preterm birth.. This was a laboratory-based study using cells and mice.. As expected, thrombin increased cyclooxygenase-2, IL-1β, IL-6, IL-8, and matrix metalloproteinase-1 in amnion mesenchymal cells. Preincubation with Nrf2 activators, diethyl maleate or 15-deoxy-Δ12, 14-prostaglandin J2 (15d-PGJ2), profoundly repressed thrombin-induced gene expression. In addition, Nrf2 activation inhibited thrombin-induced cyclooxygenase-2 protein levels and secretion of prostaglandin E2, IL-1β, IL-6, IL-8, TNFα, and granulocyte-macrophage colony-stimulating factor in the media. Whereas vehicle and 15d-PGJ2 did not alter gestational length, all pregnant mice treated with thrombin delivered preterm. 15d-PGJ2 delayed thrombin-induced preterm birth significantly.. The results indicate that Nrf2 activation represents a key stress response in amnion mesenchyme cells and in pregnant mice to mitigate the adverse proinflammatory effects of thrombin on the fetal membranes. We suggest, therefore, that pharmacological activation of Nrf2 may prevent the increased risk of preterm premature rupture of the membranes associated with thrombin activation that accompanies subchorionic hemorrhage or bleeding during pregnancy.

Topics: Amnion; Animals; Cyclooxygenase 2; Female; Gestational Age; Humans; Interleukin-1beta; Interleukin-6; Interleukin-8; Maleates; Matrix Metalloproteinase 1; Mice; NF-E2-Related Factor 2; Pregnancy; Premature Birth; Prostaglandin D2; Thrombin

Animals have evolved defense systems for surviving in a chemically diverse environment. Such systems should demonstrate plasticity, such as adaptive immunity, enabling a response to even unknown chemicals. The antioxidant transcription factor Nrf2 is activated in response to various electrophiles and induces cytoprotective enzymes that detoxify them. We report here the discovery of a multiple sensing mechanism for Nrf2 activation using zebrafish and 11 Nrf2-activating compounds. First, we showed that six of the compounds tested specifically target Cys-151 in Keap1, the ubiquitin ligase for Nrf2, while two compounds target Cys-273. Second, in addition to Nrf2 and Keap1, a third factor was deemed necessary for responding to three of the compounds. Finally, we isolated a zebrafish mutant defective in its response to seven compounds but not in response to the remaining four. These results led us to categorize Nrf2 activators into six classes and hypothesize that multiple sensing allows enhanced plasticity in the system.

Topics: Animals; Antioxidants; Carrier Proteins; Cysteine; Embryo, Nonmammalian; Gene Expression Regulation; Glutathione S-Transferase pi; Hydrogen Peroxide; Maleates; Mutation; NF-E2-Related Factor 2; Oxidative Stress; Prostaglandin D2; Response Elements; Transcriptional Activation; Zebrafish; Zebrafish Proteins

The liberation of arachidonic acid and the production of prostaglandin D2 (PGD2) were significantly influenced by peroxide and the level of intracellular glutathione (GSH). The productions of free arachidonic acid and PGD2 in RBL-2H3 cells were enhanced considerably by exposure to tert-butyl hydroperoxide (t-BHP). The liberation of arachidonic acid induced by t-BHP was not inhibited by EGTA. The productions of PGD2 and arachidonic acid induced by t-BHP were significantly facilitated by the depletion of intracellular GSH using buthionine sulfoximine (BSO) or diethyl maleate (DEM), although the depletion of GSH had no effect on the production of PGD2 induced by A23187. t-BHP failed to activate the conversion of free arachidonic acid to PGD2, since the formation of PGD2 from exogenously added arachidonic acid was not enhanced by treatment with t-BHP. The level of lipid hydroperoxides in t-BHP-treated cells was significantly elevated by treatment with DEM. These results suggest that hydroperoxides increase the free arachidonic acid available for the synthesis of PGD2 by activating phospholipase A2 (PLA2) and that the depletion of GSH by DEM accelerates the activation of PLA2 by raising peroxide levels in cells. Thus, the observed alterations in GSH levels are large enough to cause increased PGD2 synthesis in RBL-2H3 cells exposed to oxidative stress.

Topics: Animals; Arachidonic Acid; Buthionine Sulfoximine; Calcimycin; Cyclooxygenase 1; Glutathione; Intramolecular Oxidoreductases; Ionophores; Isoenzymes; Leukemia, Experimental; Lipocalins; Maleates; Membrane Proteins; Oxidants; Oxidation-Reduction; Phospholipids; Prostaglandin D2; Prostaglandin-Endoperoxide Synthases; Rats; tert-Butylhydroperoxide; Tumor Cells, Cultured

Delta 12-Prostaglandin (PG) J2 caused porcine aortic endothelial cells to synthesize a 31,000-dalton heme oxygenase and a 67,000-dalton protein (p67). Treatment of the cells with buthionine sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, depleted intracellular GSH, and enhanced the induction of heme oxygenase and p67 syntheses by delta 12-PGJ2. In contrast, treatment with GSH increased the intracellular GSH level and reduced the induction. There was a reciprocal relationship between the level of intracellular GSH, and that of the induction of heme oxygenase and p67 syntheses by delta 12-PGJ2. An increase in the intracellular GSH level caused an increase in the ethyl acetate-unextractable form of delta 12-PGJ2 in the cytosol, but suppressed the accumulation of delta 12-PGJ2 in the nuclei. Furthermore, GSH strongly inhibited the in vitro binding of delta 12-PGJ2 to isolated nuclei, which is N-ethylmaleimide sensitive. Moreover, the induction of heme oxygenase and p67 syntheses by the thiol-reactive agents arsenite and diethylmaleate was also inhibited by GSH treatment and enhanced by BSO treatment. These results demonstrate that intracellular GSH suppresses delta 12-PGJ2-induced heme oxygenase and p67 syntheses by inhibiting the binding of delta 12-PGJ2 to nuclei.

Topics: Animals; Aorta; Arsenic; Arsenites; Cell Nucleus; Cells, Cultured; DNA-Binding Proteins; Drug Interactions; Endothelium, Vascular; Glutathione; Heme Oxygenase (Decyclizing); Maleates; Nuclear Proteins; Prostaglandin D2; Serum Response Factor; Swine

The major dehydration product of prostaglandin D2, 9-deoxy-delta 9,delta 12(E)-prostaglandin D2, is a potent cytotoxic compound. Like other cytotoxic prostaglandins, this compound possesses an alpha, beta-unsaturated ketone group to which cytotoxic activity has been attributed. This prostaglandin was found to readily conjugate with glutathione (GSH) in vitro. When 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 was incubated with Chinese hamster ovary or hepatoma tissue culture cells, it was rapidly taken up and was recovered in the cell lysate primarily as a GSH conjugate in which the keto group at C-11 and the delta 12 double bond had been reduced. Identification of the GSH conjugate was accomplished by analysis by fast atom bombardment mass spectrometry following purification by high performance liquid chromatography. This GSH conjugate and its cysteinylglycinyl and cysteinyl metabolites were also identified in the cell culture medium. 9-Deoxy-delta 9,delta 12(E)-prostaglandin D2 inhibited cell proliferation of these two cell lines in a concentration dependent manner. Depletion of intracellular glutathione by treatment with diethyl maleate and buthionine sulfoximine decreased the amount of intracellular conjugated prostaglandin recovered, and significantly enhanced the antiproliferative effect of 9-deoxy-delta 9-delta 12(E)-prostaglandin D2 on the growth of these cell lines in a concentration dependent fashion. We conclude that intracellular GSH may modulate the antiproliferative activity of 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 and, possibly, of other cytotoxic prostaglandins.

Topics: Animals; Antimetabolites; Antineoplastic Agents; Biological Transport; Biotransformation; Buthionine Sulfoximine; Cell Division; Cell Line; Glutathione; Maleates; Mass Spectrometry; Methionine Sulfoximine; Prostaglandin D2; Tritium