Donna M. Slater

Expression of cyclooxygenase types 1 and 2 in human fetal membranes at term

OBJECTIVE Our purpose was to compare the level of expression of both type 1 and type 2 cyclooxygenase genes before and after labor and to localize their expression within the fetal membranes. STUDY DESIGN The sites of type 2 and type 1 cyclooxygenase messenger ribonucleic acid synthesis were identified with in situ hybridization. Expression of both types 1 and 2 cyclooxygenase was studied by reverse transcriptase polymerase chain reaction. RESULTS Cyclooxygenase type 2 and type 1 expression was localized within the amniotic epithelium and amniotic mesoderm. Type 1 but not type 2 enzyme was also expressed in the chorionic mesoderm. Expression of the type 2 enzyme was significantly increased with the onset of labor. Type 1 enzyme expression did not significantly change with labor. CONCLUSION It is most likely that it is the inducible type 2 cyclooxygenase enzyme that mediates the increase in prostaglandin synthesis in amnion with the onset of labor.

Use of a cyclo-oxygenase type-2-selective non-steroidal anti-inflammatory agent to prevent preterm delivery

Vol 350 • July 26, 1997 265 gene deletion (figure, bottom). We interpreted the finding of cells with VHL-gene deletion in the lymphnode as possibly indicating the presence of tumour cells. Because of the discrepancy between the FISH analysis and morphological analysis, we made deeper cuts into the tissue block which showed one small focus of metastatic tumour cells. Identification of single neoplastic cells with the use of immunohistochemistry of in-situ hybridisation for RNA expression may be ambiguous but detection of genetic deletion by FISH may be more definite. Furthermore, both the opposite allele and the centromeric probe serve as internal controls within the same cell, and screening of lymphoid tissue may provide control lymphocytes with constitutional genotype (figure, middle). These findings suggest that single metastatic tumour cells may be detected in lymphnode tissue before the formation of a characteristic tumour architectural pattern. Allelic deletion of the VHL gene is not only seen in VHL disease-related renal cell carcinoma, but also in many cases of sporadic RCC suggesting that screening for neoplastic cells by FISH could be useful in many cases of RCC. Also, the deletion status of individual patients may be obtained by analysing biopsy material before nephrectomy. Whether scattered dissemination of tumour cells before architectural differentiation represents a common mechanism of tumour-cells metastasis remains to be established.

A role for noradrenaline in pre‐eclampsia: towards a unifying hypothesis for the pathophysiology

Objective To compare plasma catecholamine (noradrenaline and adrenaline) levels in pre‐eclamptic to normotensive pregnancy, and to study the activity of synthetic enzymes for catecholamines in placental and trophoblastic cell cultures. We postulated that catecholamines might be an important signal secreted by the fetoplacental unit in pre‐eclampsia.

Induction of both cytosolic phospholipase A2 and prostaglandin H synthase-2 by interleukin-1 β in WISH cells is inhibited by dexamethasone

In previous studies we have shown that IL-1 beta induced both PGE2 release and total cellular cPLA2 activity and cPLA2 protein synthesis in human amnion-derived WISH cells. In this study, the effect of IL-1 beta on cPLA2 and PGHS-2 mRNA expression was investigated. Using RT-PCR, we found that IL-1 beta (0.1 ng/ml) coordinately induced both cPLA2 and PGHS-2 mRNA expression within 2 hours. The synthetic glucocorticoid dexamethasone (10(-10)-10(-6)M) inhibited IL-1 beta-induced cPLA2 and PGHS-2 mRNA expression activity and protein synthesis and PGE2 release in a concentration dependent manner. In the absence of IL-1 beta, dexamethasone alone (10(-6)M) inhibited basal cPLA2 activity, mRNA expression and protein synthesis. In addition, cycloheximide (5 micrograms/ml) apparently superinduced, but actinomycin D (2 micrograms/ml) inhibited IL-1 beta-induced cPLA2 and PGHS-2 mRNA expression suggesting that both are immediate early genes and a transcriptional mechanism is involved in the induction of both cPLA2 and PGHS-2 mRNA by IL-1 beta.

Changes in amniotic arachidonic acid metabolism associated with increased cyclo-oxygenase gene expression

Objectives To study the differences in the metabolism of arachidonic acid, to prostaglandins and other eicosanoids, between amnion cells before and after labour. To study the changes in the expression of the type 1 cyclo‐oxygenase gene associated with the changes in arachidonic acid metabolism.

The expression of phospholipase A2 and lipocortins (annexins) I, II and V in human fetal membranes and placenta in association with labour

We have studied the expression of the cellular, type two phospholipase A2 and lipocortins (annexins) I, II and V in human amnion, chorion-decidua and placenta using northern analysis. We found no difference in the expression of phospholipase A2 or lipocortin V in tissues obtained before or after labour. Lipocortin I expression was found to decrease in amnion and placenta but increase in chorion decidua with the onset of labour, while expression of lipocortin II increased only in amnion. These results support the hypothesis that the increased phospholipase A2 activity in the fetal membranes and placenta which is associated with labour is not due to increased phospholipase A2 gene expression, but that post translational control of phospholipase A2 activity may be mediated through changes in lipocortin I expression.

Prostaglandin E2 Represses Interleukin 1 Beta-Induced Inflammatory Mediator Output From Pregnant Human Myometrial Cells Through the EP2 and EP4 Receptors

ABSTRACT Inflammatory mediators, including prostaglandins, cytokines, and chemokines, are strongly implicated in the mechanism of human labor, though their precise roles remain unknown. Here we demonstrate that interleukin 1 beta (IL-1beta) significantly increased the expression and release of interleukin-8 (CXCL8), monocyte chemotactic protein-1 (CCL2), and granulocyte macrophage colony-stimulating factor (CSF2) by primary human myometrial cells. However, this effect was repressed by prostaglandin E2 (PGE2). As PGE2 can activate four distinct PGE2 receptors (EP1, EP2, EP3, and EP4) to elicit various responses, we sought to define the EP receptor(s) responsible for this repression. Using selective EP receptor agonists and a selective EP4 antagonist, we show that PGE2 mediates the repression of IL-1beta-induced release of CXCL8, CCL2, and CSF2 via activation of the EP2 and EP4 receptors. The use of siRNA gene-specific knockdown further confirmed a role for both receptors. Real-time RT-PCR demonstrated that EP2 was the most highly expressed of all four EP receptors at the mRNA level in human myometrial cells, and immunocytochemistry showed that EP2 protein is abundantly present throughout the cells. Interestingly, PGE2 does not appear to reduce mRNA expression of CXCL8, CCL2, and CSF2. Our results demonstrate that PGE2 can elicit anti-inflammatory responses via activation of the EP2 and EP4 receptors in lower segment term pregnant human myometrial cells. Further elucidation of the EP receptor-mediated signaling pathways in the pregnant human uterus may be beneficial for optimizing the maintenance of pregnancy, induction of labor or indeed treatment of preterm labor.