Labour is associated with increased expression of type-IIA secretory phospholipase A2 but not type-IV cytosolic phospholipase A2 in human myometrium

Human labour is associated with increased prostaglandin synthesis within the uterus. The aim of this study was to examine the expression of the type-IV cytosolic phospholipase A2 (cPLA2-IV) and the type IIA secretory phospholipase A2 (sPLA2-IIA) in myometrium in association with labour onset at term and preterm deliveries. These enzymes are important for the release of the prostaglandin precursor, arachidonic acid, from phospholipid membrane stores. RT-PCR was used to determine differences in gene expression between non-labour and labour groups. Expression of sPLA2-IIA in human myometrium was significantly increased with pregnancy, and with labour, both at term and preterm. Expression of cPLA2-IV in myometrium was not significantly altered with respect to pregnancy or labour. Immunohistochemical analysis demonstrated differences in the spatial localization of cPLA2-IV and sPLA2-IIA protein in upper and lower segment myometrium. cPLA2-IV was predominantly in vascular endothelial cells, while sPLA2-IIA was observed in vascular, endothelial and smooth muscle cells. In addition, sPLA2-IIA showed a distinct nuclear or perinuclear localization in myometrial smooth muscle cells of the lower segment. We postulate that the increased expression of sPLA2-IIA rather than cPLA2-IV in the myometrium may play a role in the onset and/or maintenance of human parturition.     

Expression and regulation of prostaglandin E synthase isoforms in human myometrium with labour

Since the controversies regarding the use of non-steroidal anti-inflammatory drugs (NSAIDs) and selective cyclo-oxygenase (COX)-2 antagonists for the treatment of preterm labour (PTL), more emphasis has been placed on investigating the terminal synthases involved in the production of prostaglandins (PGs) to allow more targeted therapy in PTL. Prostaglandin E(2) (PGE(2)) is synthesized by one of three enzymes, cytosolic prostaglandin E synthase (cPGES), microsomal PGES-1 (mPGES-1) and microsomal PGES-2 (mPGES-2). We have determined (i) the immuno-localization of all three PGES enzymes in lower segment pregnant human myometrium, (ii) the expression of PGES and COX-2 mRNA expression at term and preterm gestation with and without labour and (iii) the effect of interleukin (IL)-1beta on COX-2 and PGES mRNA and protein expression in human myometrial smooth muscle (HMSM) cell cultures. We show mPGES-1 protein located predominantly in myometrial and vascular smooth muscle cells (SMCs), whilst mPGES-2 protein is largely in stromal cells surrounding the SMC and cPGES is diffusely located throughout the myometrium. Expression of mPGES-2 mRNA increased with term labour and PTL and expression of COX-2 and mPGES-1 mRNA with term labour, whereas cPGES expression did not change. IL-1beta stimulated release of PGE(2) by HMSM cells and increased COX-2 and mPGES-1 mRNA and protein expression. Thus, COX-2 expression and mPGES-1 expression are co-ordinately up-regulated in lower segment myometrium with term labour and with IL-1beta treatment in HMSM cells.     

Differential expression of the metalloproteinase MMP3 and the alpha5 integrin subunit in human myometrium at labour

Extensive tissue remodelling occurs in the human myometrium before, during and after parturition. The aim of this study was to investigate the expression of two tissue remodelling molecules, matrix metalloproteinase 3 (MMP3) and alpha5 integrin (ITGA5) subunit in human myometrium, during pregnancy and labour. mRNA and protein were isolated from human pregnant labouring and non-labouring myometrial tissue, and also from human primary uterine smooth muscle cells (SMCs). Semi-quantitative RT-PCR, real-time fluorescence RT-PCR and western blotting were subsequently performed to determine the expression levels of MMP3 and ITGA5 in the myometrial tissues during pregnancy and labour, and in the primary uterine SMCs. The expression of MMP3 and ITGA5 mRNA and protein are reported for the first time during pregnancy and labour in human myometrium. Furthermore, a significant increase in expression of MMP3 mRNA (41-fold, P = 0.001), and a significant decrease in ITGA5 mRNA expression (4-fold, P < 0.001) at labour, were observed. Protein expression of these two molecules was also altered at labour, pro-MMP3 protein expression significantly increased while ITGA5 protein expression decreased, with labour onset. Expression of these molecules was also observed in primary cultured human uterine SMCs. The differential expression of these two tissue remodelling molecules at labour and their detection in uterine SMCs highlights their potential importance in myometrial function during pregnancy, labour and post-partum.     

Seminal plasma activates cyclooxygenase-2 and prostaglandin E2 receptor expression and signalling in cervical adenocarcinoma cells

Enhanced cyclooxygenase (COX) expression and prostaglandin E2 (PGE2) synthesis are regarded as promoters of neoplastic cell proliferation and angiogenesis. Expression of COX-2 and synthesis of PGE2 are up-regulated in cervical carcinomas. In sexually active women, growth and invasiveness of neoplastic cervical epithelial cells may be also under the direct influence of PGE2 present in seminal plasma. The aims of this study were to investigate the effect of seminal plasma and PGE2 on the expression of COX-2 and expression and signalling of the PGE2 receptor subtypes (EP1-EP4) in HeLa (cervical adenocarcinoma) cells. Treatment of HeLa cells with seminal plasma or PGE2 resulted in up-regulation of COX-2 expression (P < 0.05). In addition, seminal plasma induced the mRNA expression of EP1, EP2 and EP4 receptors, whilst PGE2 treatment of HeLa cells induced the expression of the EP4 receptor (P < 0.05). This was coincident with a rapid accumulation of adenosine 3',5'-cyclic monophosphate (cAMP) in HeLa cells stimulated with seminal plasma or PGE2, which was greater in seminal plasma stimulated cells compared with PGE2 stimulated cells (P < 0.05). Subsequently, we investigated whether the effect of seminal plasma on cAMP signalling in HeLa cells was mediated via the cAMP-linked EP2/EP4 receptors. Stimulation of HeLa cells with seminal plasma or PGE2 resulted in an augmented cAMP accumulation in cells transfected with the EP2 or EP4 receptor cDNA compared with control transfected cells (P < 0.05). These data suggest that, in sexually active women, seminal plasma may play a role in modulating neoplastic cell function and cervical tumorigenesis.     

Myometrial prostaglandin E2 synthetic enzyme mRNA expression: spatial and temporal variations with pregnancy and labour

We have investigated the hypothesis that the expression of the enzymes involved in PGE(2) synthesis in the human uterus is co-ordinated. We have studied (i) the mRNA expression of the enzymes involved in PGE(2) synthesis [phospholipases (cPLA(2) and sPLA(2)), prostaglandin H synthase (PGHS)-2 and PG E synthases (PGES-1 and -2)] and their relationship to the expression of inflammatory cytokines in samples of myometrium obtained from pregnant women undergoing caesarean section (LSCS) either before or after the onset of labour at or before term; and (ii) the effect of IL-1beta, IL-6, TNF-alpha, PGE(2) and stretch on PGE(2) enzyme mRNA expression. We found that cPLA(2), sPLA(2) and PGHS-2 mRNA expression were greater in labour samples; cPLA(2), sPLA(2), PGHS-2, PGES-1 and -2 mRNA expression were greater in lower- than upper-segment samples; and there was no effect of gestational age. PGHS-2 mRNA levels correlated with those of PGES-1, cPLA(2), IL-1beta and IL-8; PGES-1 mRNA levels correlated with those of IL-1beta, IL-8 and cPLA(2). In primary cultures of uterine myocytes, cPLA(2) mRNA expression was increased by IL-1beta and IL-6; PGHS-2 mRNA expression was increased by IL-1beta, PGE(2) and stretch; and PGES-1 mRNA expression was increased by IL-1beta only. These data show that labour is associated with increased expression of the enzymes involved in PGE(2) synthesis and their expression is greater in the lower uterine segment. The presence of associations between the levels of PGE(2) enzyme mRNA expression and the effects of IL-1beta suggest that their expression is co-ordinated and that IL-1beta is the responsible factor.     

Seminal plasma and prostaglandin E2 up-regulate fibroblast growth factor 2 expression in endometrial adenocarcinoma cells via E-series prostanoid-2 receptor-mediated transactivation of the epidermal growth factor receptor and extracellular signal-regulated kinase pathway

BACKGROUND: Prostaglandin E(2) (PGE(2)) has been shown to modulate angiogenesis and tumour progression via the E-series prostanoid-2 (EP2) receptor. Endometrial adenocarcinomas may be exposed to endogenous PGE(2) and exogenous PGE(2), present at high concentration in seminal plasma. METHODS: This study investigated fibroblast growth factor 2 (FGF2) mRNA expression and cell signalling in response to seminal plasma or PGE(2), using an endometrial adenocarcinoma (Ishikawa) cell line stably expressing the EP2 receptor (EP2 sense cells) and endometrial adenocarcinoma explants. RESULTS: Seminal plasma and PGE(2) induced a significant up-regulation of FGF2 expression in EP2 sense but not parental untransfected Ishikawa (wild-type) cells (P < 0.05). These effects were inhibited by co-treatment with EP2 receptor antagonist or inhibitors of protein kinase A, c-Src, epidermal growth factor receptor (EGFR) kinase or extracellular signal-regulated kinase (ERK) signalling. The treatment of EP2 sense cells with seminal plasma induced cAMP accumulation and phosphorylation of c-Src, EGFR kinase and ERK via the EP2 receptor. Finally, seminal plasma and PGE(2) significantly increased FGF2 mRNA expression in endometrial adenocarcinoma tissue explants via the EP2 receptor (P < 0.05). CONCLUSIONS: Seminal plasma and PGE(2) can similarly activate FGF2 expression and EP2 receptor signalling in endometrial adenocarcinoma cells. These data highlight the potential for seminal plasma exposure to facilitate tumorigenesis-angiogenesis in endometrial adenocarcinomas in vivo.     

Interleukin-11 expression: its significance in eutopic and ectopic human implantation

Embryo implantation and subsequent decidualization, trophoblast invasion and formation of a functional placenta are crucial for establishment and maintenance of pregnancy. Interleukin-11 signalling has been shown to be obligatory for adequate decidualization and trophoblast invasion in mice. Defects in IL-11 signalling in mice result in trophoblast over-invasion and fetal loss. The pathological situation of human tubal pregnancy resembles that of IL-11Ralpha(-/-) mice concerning these symptoms. As our interest is focused on the human early pregnancy, we compared IL-11 expression at the implantation site of ectopic tubal pregnancy (EP) to 1st and 2nd trimester of normal intrauterine pregnancies (IP), and to the normal cycling endometrium. The mRNA expression of IL-11 and IL-11Ralpha was analysed by semiquantitative RT-PCR. Protein expression was detected by western blotting and immunohistochemistry. IL-11Ralpha is expressed constitutively in all tissue specimens analysed. IL-11 is expressed predominantly during follicular and early luteal phase of the menstrual cycle. In IP, IL-11 expression peaks during the 1st trimester and declines from the beginning of the 2nd trimester onwards. In tubal abortions, IL-11 expression is reduced in comparison to vital EP and IP. Cultured primary endometrial and decidual epithelial cells were analysed for hormonal regulation of IL-11 by enzyme-linked immunosorbent assay and RT-PCR. IL-11 is up-regulated by estrogen and down-regulated by progesterone. Overall, our results indicate that in humans, IL-11 signalling is significantly involved in regulation of trophoblast invasion. In the case of tubal abortion, inadequate IL-11 signalling may therefore result in dysregulation of trophoblast invasion.     

机动车尾气诱发大鼠慢性阻塞性肺疾病并上调气道上皮细胞COX-2/PGE2/EP受体信号通路

目的：探究机动车尾气(MVE)长期暴露引起大鼠慢性阻塞性肺疾病(COPD)发生时,气道上皮细胞中环加氧酶2(COX-2)/前列腺素E₂(PGE₂)/E-前列腺素类激素(EP)受体信号通路成员的表达变化。方法：(1)动物实验：健康雄性SD纯系大鼠(SPF级)16只,随机分为2组：MVE暴露组(n=8)和空白对照(CTL)组(n=8)。采用MVE暴露6个月的方法建立COPD大鼠模型。造模结束后,使用Buxco小动物有创肺功能仪检测大鼠肺功能;肺组织切片行HE染色并评估肺组织病理变化;ELISA法检测大鼠支气管肺泡灌洗液(BALF)中炎症因子白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)和PGE₂的水平,评估大鼠肺部炎症情况;采用免疫荧光及Western blot法检测肺组织COX-2及EP受体蛋白水平;提取肺组织核蛋白,Western blot检测MVE对肺组织NF-κB核转位的影响。(2)细胞实验：采用MVE细颗粒物(PM2.5)标准品刺激人正常支气管上皮细胞BEAS-2B。ELISA法检测细胞培养液中PGE     

Leukocytes infiltrate the myometrium during human parturition: further evidence that labour is an inflammatory process.

Inflammatory mediators in the cervix, placenta and fetal membranes play a crucial role in human parturition. The aim of this study was to determine whether the upper and lower segments of the myometrium are infiltrated by inflammatory cells during pregnancy and parturition. Myometrial biopsies were obtained from non-pregnant women, and pregnant women at term before and after the onset of spontaneous labour. Subpopulations of inflammatory cells were identified using immunocytochemistry. The intercellular adhesion molecules, 1 and 2, platelet endothelial cell adhesion molecule, vascular cell adhesion molecule and E-selectin were immunolocalized to investigate their involvement in leukocyte accumulation. Histological analysis demonstrated that inflammatory cells, predominantly neutrophils and macrophages, infiltrate human myometrium during spontaneous labour at term. The infiltrate is predominant in the lower uterine segment but is also present in the upper segment. Increased expression of E-selectin was found on the vascular endothelium of biopsies obtained during labour, suggesting a role for this molecule in the accumulation of leukocytes. These results suggest that inflammatory cell infiltration is part of the physiological mechanisms that occur in the myometrium during parturition. Further understanding of this process may suggest new strategies aimed at preventing preterm delivery.     

5 Beta-dihydroprogesterone and steroid 5 beta-reductase decrease in association with human parturition at term

The role of progesterone withdrawal in human parturition continues to provoke controversy. One possible mechanism by which functional progesterone withdrawal may be achieved is by a decrease in the circulating concentration of its bioactive metabolites. The progesterone metabolite 5beta-dihydroprogesterone (5betaDHP) has been shown to be a potent tocolytic in vitro. We quantified plasma concentrations of 5betaDHP in association with the onset of spontaneous labour in women at term and steroid 5beta-reductase mRNA expression in placenta, myometrium, chorion and amnion in relation to parturition, using real time RT-PCR. Serial blood samples were obtained from patients late in pregnancy, before term labour, during term labour and within the first 24 h postpartum. Following organic solvent extraction, steroids including 5betaDHP were separated by high-performance liquid chromatography (HPLC) and then quantified by radioimmunoassay (RIA). 5betaDHP concentration decreased two-fold (P = 0.00001, n = 25) from 0.317 +/- 0.039 nmol/ml to 0.178 +/- 0.017 nmol/ml in association with active labour. Tissue 5beta-reductase mRNA-relative abundance was determined in placenta, myometrium, chorion and amnion obtained from labouring and non-labouring women. In placenta and myometrium, relative expression decreased significantly in association with labour, by about two-fold and 10-fold, respectively. These data are consistent with a possible role for 5betaDHP in the onset of spontaneous human labour. Further studies exploring this hitherto unrecognized endocrinological pathway are indicated.     

Inhibitory effects of PGE(2) on K(+) currents and Ca(2+) oscillations in rat pancreatic acinar cells

Prostaglandin E(2) (PGE(2)) inhibits pancreatic enzyme secretion and shows a protective action against pancreatitis. In this study, we tested the effects of PGE(2) on the slowly activating voltage-dependent K(+) channel current ( I(Ks)) and cholecystokinin (CCK)-induced oscillations of cytosolic [Ca(2+)] ([Ca(2+)](i)) in rat pancreatic acini (RPA). I(Ks) in RPA is reportedly augmented by both Ca(2+)- and cAMP-mediated secretagogues. PGE(2) (10(-7) M) decreased the amplitude of I(Ks), an effect that was more prominent following prior stimulation with secretin. The application of the membrane-permeable cAMP analogue 8-Br-cAMP prevented the effect of PGE(2) on I(Ks). The Ca(2+)-mediated augmentation of I(Ks) by ACh was unaffected by pretreatment with PGE(2). Using fura-2 fluorescence ratiometry to assess [Ca(2+)](i), CCK (相似文献   

Induction of prostaglandin E2 production by leukemia inhibitory factor promotes migration of first trimester extravillous trophoblast cell line, HTR-8/SVneo

BACKGROUND: The invasion of first trimester extravillous trophoblast (EVT) to decidua is an important event in placentation. Leukemia inhibitory factor (LIF) is an essential factor for mouse implantation, and it is reported that LIF may be involved in human first trimester EVT invasion. Prostaglandin E2 (PGE2) is also known as a critical factor for first trimester EVT invasion. In this study, we investigated the role of LIF in PGE2 production and EVT invasion using a human first trimester EVT cell line, HTR-8/SVneo. METHODS AND RESULTS: Co-stimulation with LIF and IL-1beta induced higher amounts of PGE2 production and further migration of HTR-8/SVneo cells compared with that by stimulation with LIF or IL-1beta alone. Enhanced PGE2 production was most probably due to the enhanced expression of cyclooxygenase-2 (COX-2) and microsomal PGE synthase-1 (mPGES-1). PGE2 produced by HTR-8/SVneo cells promoted the migration of HTR-8/SVneo cells. A COX-2 inhibitor suppressed PGE2 production and the migration of HTR-8/SVneo cells. Agonists to PGE2 receptors, EP1, EP2 and EP4, promoted the migration of HTR-8/SVneo cells. Moreover, stimulation with LIF up-regulated EP1, EP2 and EP4 expression in HTR-8/SVneo cells. CONCLUSIONS: It is suggested that LIF participates in placentation through EVT invasion by up-regulating PGE2 production and PGE2 receptor expression in first trimester EVT.     

Exploration of prostanoid receptor subtype regulating estradiol and prostaglandin E2 induction of spinophilin in developing preoptic area neurons

The prostaglandin E2 (PGE2) mediates estradiol-induced masculinization of sexual behavior in the rat during a perinatal sensitive period. PGE2 induces formation of dendritic spines on preoptic area (POA) neurons and this synaptic pattern change is associated with the ability to express male sexual behavior as an adult. Whether PGE2 is released from astrocytes or neurons in the developing POA is unknown. To further understanding of how PGE2 induces dendritic spine formation at the cellular level, we have explored the PGE2 receptor subtype mediating this response. There are four receptors for PGE2, EP1, EP2, EP3 and EP4, each having unique but interacting signal transduction profiles. Treatment of newborn female rats with the EP receptor agonists iloprost, butaprost and sulprostone indicated that stimulation of both the EP2 and EP3 receptors significantly increased spinophilin, a protein whose levels positively correlate to the presence of dendritic spines and masculinization of the POA. Use of antisense oligonucleotides against the mRNA for each receptor reveals that either EP2 or EP3 receptor knockdown reduces spinophilin in PGE2- or estradiol-treated females, whereas reducing EP1 or EP4 receptor levels by the same means has a smaller but also significant effect. A developmental profile of EP receptor expression indicates EP1 in particular is elevated for the first few days of life, corresponding to the critical period for masculinization, whereas mRNA levels for the other three receptors remain relatively constant.     

Prostaglandin E2 modulates the functional responsiveness of human monocytes to chemokines

Prostaglandin E(2) (PGE(2)) plays an important role in the immune response by modulating the complex interactions between leukocytes and tissue cells under inflammatory conditions. PGE(2) may possibly influence pro-inflammatory effects of chemokines and chemokine receptors that are among the main regulators of directional leukocyte migration. We analyzed whether PGE(2) affects chemokine receptor expression on human monocytes and their functional responsiveness to inflammatory chemokines. Expression of CCR5 on monocytes was significantly reduced, whereas CCR2 and CXCR4 expression were not affected by PGE(2). However, PGE(2 )treatment significantly increased the chemotactic response of monocytes to monocyte-chemoattractant protein-1 (MCP-1), RANTES and stromal cell-derived factor-1 (SDF-1). In addition, PGE(2) induced a higher calcium mobilization and actin polymerization upon chemokine stimulation. To better characterize PGE(2) effects, we used specific agonists for the PGE(2) receptors (EP(1) - EP(4)) characterized so far. The 11-deoxy PGE(1), an EP(2) /EP(4 )ligand, could mimic the effects observed using PGE(2). In contrast, the EP(1 )agonist, sulprostone, had not effects on monocytes, indicating that the effects of PGE(2) are mediated by EP(2)/EP(4 )receptors. Monocytes acquire a higher functional responsiveness to MCP-1, RANTES and SDF-1 after exposure to PGE(2), independently of the level of chemokine receptor expression. This mechanism might enhance the local monocyte recruitment under inflammatory conditions, and suggests specific PGE(2) receptor EP(2)/EP(4) antagonists as novel agents for the treatment of inflammatory diseases.