Expression Of Prostaglandin Receptors Research Articles

Differential Expression of Prostaglandin Receptors in Canine Uterus With Pyometra

The objective of the study was to ascertain the role of prostaglandins Viz., PGE2 and PGF2α, and their respective receptors in the pathophysiology of canine pyometra. Normal (n = 6) and pyometra (n = 8) affected uterus were collected from bitches undergoing ovariohysterectomy. Pyometra was graded according to histopathological alterations. The levels of PGE2 and PGF2α were estimated in the endometrium. The differential expression in the mRNA of PGF2α receptor (FP) and PGE2 receptors (EP1, EP2, EP3, and EP4) were studied in the endometrium and myometrium of the pyometra-affected uterus. Normal uterus served as calibrator. Elevation of both PGE2 and PGF2α levels in the endometrium of pyometra-affected bitches was observed. The FP receptor gene in the endometrium and myometrium of pyometra-affected bitches was downregulated (P < .05). Out of all EP receptors, only EP2 receptor has shown upregulation in both endometrium and myometrium of pyometra affected uterus. EP3 receptor got downregulated in both endometrium and myometrium in pyometra. Thus, downregulation of FP, EP3 receptors in the myometrium reinforces the lack of contractility in pyometra-affected bitches favoring bacterial proliferation and subsequent pus accumulation. Moreover, upregulation of EP2 receptors in the pyometra bitches suggests the scope of selective pharmacological inhibition of EP2 receptors as an adjunct therapy in the treatment of pyometra.

Resumption and progression of meiosis and circulating levels of steroids and prostaglandin F 2α of Piaractus mesopotamicus induced by hypophysation with prostaglandin F 2α

We have previously shown an increase on the ovulation rate of pacu, Piaractus mesopotamicus, using hypophysation with prostaglandin F2α (PGF2α) (HPG protocol) rather than hypophysation (H); only, however, a persistent lack of ovulation in some females could not be further explained by PGF2α and steroid plasma levels at time of ovulation. Considering this, here we compared the meiotic process and steroids and PGF2α levels during spawning induction using both protocols. To that, H and HPG were treated with conventional hypophysation (0.6 mg/kg priming and 5.4 mg/kg resolving dose), and the latter received synthetic PGF2α (2 mL/fish) at resolving dose. A negative control (saline solution), a SPG group (receiving only PGF2α) and a PPG group (receiving priming and PGF2α) were included. An initial PGF2α peak between one to four hours post-resolving dose (1-4 hr) occurred in groups receiving PGF2α (HPG, SPG and PPG). Only H and HPG showed a 17α-20β-dihydroxy-4-pregnen-3-one (DHP) peak 4 hr, concomitant with meiosis resumption, and a final PGF2α peak 12 hours. The HPG protocol resulted in higher PGF2α plasma levels for longer periods (1-4 and 12 hr) than H (single peak 12 hr), occasioning in the former higher and concomitant levels of both PGF2α and DHP at 4 h. Considering that DHP is known to induce expression of prostaglandin receptors in fish, the concomitant plasma peaks of DHP and PGF2α may also explain the ovulation rate gain previously published, using HPG protocol, which can be further improved adjusting the priming dose and defining the exact interval of PGF2α ovulatory action in this species.

FOXC1 Regulates Expression of Prostaglandin Receptors Leading to an Attenuated Response to Latanoprost.

This study examines the effect of FOXC1 on the prostaglandin pathway in order to explore FOXC1's role in the prostaglandin-resistant glaucoma phenotype commonly seen in Axenfeld-Rieger syndrome. Binding and transcriptional activity of FOXC1 to the gene coding for the EP3 prostaglandin receptor (PTGER3) were evaluated through ChIP-qPCR and luciferase-based assays. Immortalized trabecular meshwork cells (TM1) and HeLa cells had FOXC1 mRNA reduced via siRNA interference. qPCR and Western blot experiments were conducted to examine the changes in prostaglandin receptor expression brought about by lowered FOXC1. TM1 cells were then treated with 10 μM latanoprost acid and/or an siRNA for FOXC1. The expression of fibronectin and matrix metalloproteinase 9 were evaluated via qPCR in each treatment condition. ChIP-qPCR and luciferase experiments confirmed that FOXC1 binds to and activates transcription of the EP3 gene prostaglandin receptor. qPCR and Western experiments in HeLa and TM1 cells showed that FOXC1 siRNA knockdown results in significantly lowered EP3 levels (protein and RNA). In addition, RNA levels of the other prostaglandin receptor genes EP1 (PTGER1), EP2 (PTGER2), EP4 (PTGER4), and FP (PTGFR) were altered when FOXC1 was knocked down in TM1 and HeLa cells. Analysis of fibronectin expression in TM1 cells after treatment with 10 μM latanoprost acid showed a statistically significant increase in expression; this increase was abrogated by cotreatment with a siRNA for FOXC1. We show the abrogation of latanoprost signalling when FOXC1 is knocked down via siRNA in a trabecular meshwork cell line. We propose that the lower levels of active FOXC1 in Axenfeld-Rieger syndrome patients with glaucoma account for the lack of response to prostaglandin-based medications.

Misoprostol modulates the gene expression prostaglandin E2 and oxidative stress markers in myometrial cells

Misoprostol, prostaglandin E1 analogue, used for labour induction. However, one-third of patients who have labour induced with prostaglandins do not reach vaginal delivery. The differential expression of prostaglandin receptors in myometrial cells could account for this differential response. Since delivery physiology also involves modulation of oxidative metabolism that can be potentially affected by pharmacological drugs, in the present investigation the role of misoprostol on expression of prostaglandin receptors, and oxidative markers of myometrial cells was evaluated. Samples of myometrial tissues procured from women with spontaneous (SL) and nonspontaneous (NSL) labours were cultured in vitro and exposed to different concentrations of misoprostol. Gene expression was evaluated by qRT-PCR and oxidative biomarkers were evaluated by spectrophotometric and fluorometric analysis. Cells from SL women presented greater responsiveness to misoprostol, since an upregulation of genes related to increased muscle contraction was observed. Otherwise, cells from NSL women had low responsiveness to misoprostol exposure or even a suppressive effect on the expression of these genes. Oxidative biomarkers that previously have been related to labour physiology were affected by misoprostol treatment: lipoperoxidation and protein carbonylation (PC). However, a decrease in lipoperoxidation was observed only in SL cells treated with low concentrations of misoprostol, whereas a decrease of PC occurred in all samples treated with different misoprostol concentrations. The results suggest a pharmacogenetic effect of misoprostol in labour induction involving differential regulation of EP receptor genes, as well as some minor differential modulation of oxidative metabolism in myometrial cells.

Resveratrol Treatment Inhibits Proliferation of and Induces Apoptosis in Human Colon Cancer Cells

BackgroundResveratrol, a natural isolate from plant sources, has a long and important history in traditional Chinese medicine. In the present study we investigated the effect of resveratrol on human colon cancer cell lines.Material/MethodsWe used the Cell Counting kit-8 (CCK-8) for determination of colon cancer cell viability. Apoptosis induction was analyzed using the DeadEnd™ Colorimetric TUNEL System (Promega, Madison, WI, USA). The siRNA Transfection Reagent kit (Santa Cruz Biotechnology, Inc.) was used for the administration of COX-2 silencer RNA (siRNA) into the colon cancer cells. Primer Express® software for Real-Time PCR ver. 3.0 (Applied Biosystems, Foster City, CA, USA) was used to prepare the primers for RT-PCR.ResultsThe results revealed that exposure of colon cancer cells to resveratrol inhibited cell viability. Resveratrol exhibited a significant inhibitory effect on cell viability at 30 μM concentration after 48 h of exposure. We observed that 30-μM doses of resveratrol for 72 h led to 18, 29, and 34% reduction in the viability of HCA-17, SW480, and HT29 cells, respectively. It also significantly induced apoptosis in both of the tested carcinoma cell lines. The population of apoptotic cells in HCA-17 and SW480 cell lines after 48 h of resveratrol treatment was 59.8±4 and 67.2±4%, respectively, compared to 2.3±1% in the control cells. The colon cancer cells exposed to resveratrol showed significantly lower cyclooxygenase-2 and prostaglandin receptor expression. Treatment of colon cancer cells with the inhibitor of cyclooxygenase-2, indomethacin, and administration of silencer RNA for cyclooxygenase-2 also produced similar results.ConclusionsThese findings suggest that resveratrol treatment can be a promising strategy for the treatment of colon cancer.

Expression of prostaglandin receptors in Chlamydia trachomatis-infected recurrent spontaneous aborters.

A study was undertaken to quantify the expression of prostaglandin (PG) receptors and find the effect of gestational age on expression of PG receptor genes in Chlamydia trachomatis-infected recurrent spontaneous aborters (RSA). Endometrial curettage tissue (ECT) was collected from 130 RSA (Group I) and 100 age-matched controls (Group II) at the Department of Obstetrics and Gynecology, Safdarjung Hospital, New Delhi (India). PCR was performed for diagnosis of C. trachomatis cryptic plasmid; mRNA expression of PG receptor genes was assessed by real-time PCR (q-PCR), while serum progesterone/estrogen levels were determined by respective commercial kits. Data were evaluated statistically. A total of 15.4 % RSA (GroupI) were diagnosed as C. trachomatis-positive (200 bp), whereas controls were uninfected. q-PCR showed significant upregulation (P<0.0001) of PGE2 (EP-1, EP-2, EP-3, EP-4), PGF2α (FP) and PGI2 (IP) receptors in Group I versus Group II. The expression of PG receptors increased significantly with advanced gestational age (P<0.002); however, only contractile receptors, EP-1, EP-3 and FP, were positively correlated with gestational age in Group-I. In infected RSA, mean serum progesterone level was significantly low (P<0.0001) while serum oestrogen was high (P<0.0001). Overall, the data suggest that increased expression of PG receptors, particularly contractile gene receptors (EP-1, EP-3, FP), with advanced gestational age and altered steroid levels could be a possible risk factor for abortion in Chlamydia-infected RSA.

Prostaglandin E2 impairs osteogenic and facilitates adipogenic differentiation of human bone marrow stromal cells

The synthetic glucocorticoid dexamethasone (dex) is a mandatory additive to induce osteogenic differentiation of bone marrow stromal cell (BMSC) in vitro; however it is also known to promote the pathogenesis of osteoporotic bone disease in vivo. In this study human (h)BMSC were cultured in osteogenic medium containing β-glycerophosphate and ascorbate (OM) and in OM containing dex (OM/D). It was seen that dex induced in human (h)BMSC both, osteogenic and adipogenic differentiation markers. Dex reveals its anti-inflammatory effect by reducing endogenous prostaglandin E2 (PGE2) formation and by suppressing the inducible enzymes cyclooxygenase 2 and microsomal PGE2 synthase 1. It was further seen that dex enhanced the expression of prostaglandin receptors, mainly EP2 and EP4 receptor subtypes. We thus hypothesized that dex enforces the susceptibility of hBMSC to respond to exogenous PGE2. Permanent exposure of hBMSC which were cultured in OM/D to PGE2, decreased osteogenic and increased adipogenic differentiation markers. The effects of PGE2 were preferentially mediated by receptor subtypes EP2 and EP4; EP1 was partially involved in pro-adipogenic effects, and EP3 was partially involved in anti-osteogenic effects. These results suggest that dex suppresses the formation of endogenous PGE2 but also enables hBMSC to respond to PGE2 due to the induction of PGE2 receptors EP2 and EP4. PGE2 then shifts in hBMSC the balance from osteogenic to adipogenic differentiation.

The expression of prostaglandin receptors EP3 and EP4 in human cervix in post‐term pregnancy differs between failed and successful labor induction

To investigate expression and localization of prostaglandin receptors EP1-4 and FP and localization of stromal factors CTGF (connective tissue growth factor), furin, calgranulin B and ALOX15 (arachidonate 15-lipooxygenase) in human cervical tissue from post-term women with failed or successful labor induction after prostaglandin priming. Experimental prospective clinical study. Tertiary obstetric care center. Twenty-six women giving birth post-term, with failed or successful labor induction, and a control group consisting of 19 women with spontaneous onset of labor and delivery at term. Biopsies were obtained from post-term women with successful (responders; R) and failed (non-responders; NR) labor induction. Women with spontaneous delivery at term were included as controls (C). mRNA expression was determined with real time PCR, protein expression and localization with immunohistochemistry. Comparisons of mRNA and protein expressions between post-term pregnancies with failed and successful labor induction as well as term controls. EP4 mRNA expression was down-regulated concomitant with an up-regulation of EP3 mRNA expression in cervix from the NR group as compared with the R group. In stroma, immunoreactivity of the EP4 protein was increased in the NR group as compared with R and C groups. Failure of cervical ripening, after local application of prostaglandins for labor induction, may be caused by the increased expression of EP3 and concomitant decrease in EP4 expression.

Vitamin D Elicits Anti-Inflammatory Response, Inhibits Contractile-Associated Proteins, and Modulates Toll-Like Receptors in Human Myometrial Cells

Infection during pregnancy triggers inflammation, which can increase myometrial contractions and the risk of premature labor and delivery. In this study, we assessed the effects of vitamin D, an anti-inflammatory ligand on cytokines, chemokines, toll-like receptors, and contractile-associated proteins on immortalized human myometrial smooth muscle (UtSM) cells stimulated with lipopolysaccharide (LPS), a bacterial endotoxin, or interleukin (IL)-1β and measured Toll-like receptor (TLR)-10 expression in pregnant myometrial tissues. A superarray analysis revealed downregulation of the chemokines monocyte chemoattractant protein (MCP)-1, Chemokine (C-X-C motif) ligand (CXCL)-10, CXCL-11, and chemokine (C-X3-C motif) ligand (CX3CL)-1; the proinflammatory cytokines IL-13 and tumor necrosis factor (TNF)-α; the TLR-4 and -5 and triggering receptor expressed on myeloid cells (TREM)-2 and upregulation of the anti-inflammatory cytokine IL-10, as well as Toll interacting protein (TOLLIP) and TREM-1 in vitamin D-treated UtSM cells. In the presence of LPS, vitamin D caused dose-dependent decreases in the messenger RNA expression of MCP-1, IL-1β, IL-13, TNF-α, TLR-4, and TLR-5, the contractile-associated proteins connexin 43, the oxytocin receptor, and the prostaglandin receptor but caused increases in IL-10 and TLR-10 in UtSM cells. The TLR-10 expression was higher in human myometrial tissue obtained from women at term not in labor compared to labor. Vitamin D also attenuated IL-1β-induced MCP-1, IL-6, connexin 43, cyclooxygenase (COX)-2, and prostaglandin receptor expression. Western analysis showed that vitamin D decreased MCP-1, TLR-4, and connexin 43 in the presence of LPS and decreased connexin 43 in the presence of IL-1β. Our results suggest that vitamin D can potentially decrease infection-induced increases in cytokines and contractile-associated proteins in the myometrium.

Mechanisms involved in PGE2-induced transactivation of the epidermal growth factor receptor in MH1C1 hepatocarcinoma cells

BackgroundIt is important to understand the mechanisms by which the cells integrate signals from different receptors. Several lines of evidence implicate epidermal growth factor (EGF) receptor (EGFR) in the pathophysiology of hepatocarcinomas. Data also suggest a role of prostaglandins in some of these tumours, through their receptors of the G protein-coupled receptor (GPCR) family. In this study we have investigated mechanisms of interaction between signalling from prostaglandin receptors and EGFR in hepatocarcinoma cells.MethodsThe rat hepatocarcinoma cell line MH1C1 and normal rat hepatocytes in primary culture were stimulated with EGF or prostaglandin E2 (PGE2) and in some experiments also PGF2α. DNA synthesis was determined by incorporation of radiolabelled thymidine into DNA, phosphorylation of proteins in signalling pathways was assessed by Western blotting, mRNA expression of prostaglandin receptors was determined using qRT-PCR, accumulation of inositol phosphates was measured by incorporation of radiolabelled inositol, and cAMP was determined by radioimmunoassay.ResultsIn the MH1C1 hepatocarcinoma cells, stimulation with PGE2 or PGF2α caused phosphorylation of the EGFR, Akt, and ERK, which could be blocked by the EGFR tyrosine kinase inhibitor gefitinib. This did not occur in primary hepatocytes. qRT-PCR revealed expression of EP1, EP4, and FP receptor mRNA in MH1C1 cells. PGE2 stimulated accumulation of inositol phosphates but not cAMP in these cells, suggesting signalling via PLCβ. While pretreatment with EP1 and EP4 receptor antagonists did not inhibit the effect of PGE2, pretreatment with an FP receptor antagonist blocked the phosphorylation of EGFR, Akt and ERK. Further studies suggested that the PGE2-induced signal was mediated via Ca2+ release and not PKC activation, and that it proceeded through Src and shedding of membrane-bound EGFR ligand precursors by proteinases of the ADAM family.ConclusionThe results indicate that in MH1C1 cells, unlike normal hepatocytes, PGE2 activates the MEK/ERK and PI3K/Akt pathways by transactivation of the EGFR, thus diversifying the GPCR-mediated signal. The data also suggest that the underlying mechanisms in these cells involve FP receptors, PLCβ, Ca2+, Src, and proteinase-mediated release of membrane-associated EGFR ligand(s).

Prostaglandin E2 is an endogenous modulator of cerebellar development and complex behavior during a sensitive postnatal period

Prostaglandins are lipid-derived molecules that mediate the generation of fever in the central nervous system. In addition to their proinflammatory role, prostaglandins also impact neuronal development and synaptic plasticity, sometimes in a sex-specific manner. The cerebellum has a high expression of prostaglandin receptors during development, but the role that these molecules play during normal cerebellar maturation is unknown. We demonstrate here that disrupting prostaglandin synthesis with cyclo-oxygenase inhibitors during a time-sensitive window in early postnatal life alters cerebellar Purkinje cell development in rats, resulting in initially increased dendritic growth in both sexes. We show that this results in later cerebellar atrophy in males only, resulting in a sex-specific loss of cerebellar volume. Further, although performance in motor tasks is spared, social interaction and the sensory threshold are altered in males developmentally exposed to cyclo-oxygenase inhibitors. This work demonstrates a previously unknown role for prostaglandins in cerebellar development and emphasizes the role that the cerebellum plays outside motor tasks, in cognitive and sensory domains that may help to explain its connection to complex neurodevelopmental disorders such as autism.

The effect of estradiol on COX-2, EP 2, and EP 4 mRNA expression and the extracellular matrix in the cervix of the hypogonadotrophic, ovariectomized ewe

There is a degree of cervical relaxation in the ewe at estrus that is regulated by changes in prostaglandin synthesis, prostaglandin receptor expression, and changes in the cervical extracellular matrix. It is likely that these are regulated by changes in periovulatory hormones, particularly estradiol. This study determined the effect of estradiol benzoate on the mRNA expression of cyclooxygenase-2 (COX-2) and the prostaglandin E receptors EP 2 and EP 4, the concentration of cervical hyaluronan, and the proportion of smooth muscle and collagen in the cervix of the hypogonadotrophic ovariectomized ewe ( Ovis aries). Ovariectomized hypogonadotrophic ewes were given 100 μg estradiol benzoate, and their cervices were collected 0, 24, and 48 h thereafter to determine the expression of cervical COX-2, EP 2, and EP 4 mRNA by in situ hybridization, the concentration of hyaluronan by ELISA, and the proportion of smooth muscle and collagen by Masson's trichrome staining. Estradiol benzoate increased the mRNA expression of COX-2 and EP 4 within 24 h after treatment (P < 0.05), whereas EP 2 mRNA, hyaluronan, and the ratio of smooth muscle to collagen did not change within 48 h after treatment. The COX-2, EP 2, and EP 4 mRNA expression were greatest in the smooth muscle layers (P < 0.05) and least in the luminal epithelium (P < 0.05). In conclusion, we inferred that estradiol regulates cervical COX-2 and EP 4 mRNA expression and may regulate cervical relaxation via the synthesis of prostaglandin E 2 and activation of the PGE 2 receptors EP 2 and EP 4.

IL-1β Stimulates the Expression of Prostaglandin Receptor EP4 in Human Chondrocytes by Increasing Production of Prostaglandin E2

Prostaglandin (PG) E2, which exerts its actions via the PG receptors EP1–4, is produced from arachidonic acid by cyclooxygenase (COX)-1 and COX-2. The aim of this study was to investigate the mechanisms by which interleukin (IL)-1β induces the expression of PG receptors in cultured human chondrocytes and to explore the role of PGE2 in this process. The cells were cultured with 0, 10, or 100 U/mL IL-1β with or without 1 μM celecoxib, a specific inhibitor of COX-2, for up to 28 days. Expression of the genes encoding COX-1, COX-2, and EP1–4 was quantified using real-time PCR, and expression of the corresponding proteins was examined using immunohistochemical staining. PGE2 production was determined using ELISA. IL-1β treatment caused a marked dose- and time-dependent increase in the levels of PGE2, COX-2, and EP4 as compared with the untreated control. It did not affect the expression of COX-1, and it decreased the expression of EP1 and EP2. EP3 expression was not detected in either the absence or the presence of IL-1β. When celecoxib was also present, IL-1β failed to stimulate PGE2 production and EP4 expression, but its stimulatory effect on COX-2 expression and its inhibitory effect on EP1 and EP2 expression were unchanged. IL-1β increases the production of PGE2, COX-2, and the PG receptor EP4 in cultured human chondrocytes. The increase in EP4 expression appears to be a result of the increased PGE2 production.

Prostaglandin receptors mediate effects of substances released from ischaemic rat hearts on non‐ischaemic cardiomyocytes

After ischaemia and during reperfusion, rat hearts release cardiodepressive substances that are putatively cyclooxygenase-2-dependent. The present study analyses the mechanisms by which these substances mediate their effect downstream of cyclooxygenase-2. After 10 min of global stop-flow ischaemia, isolated rat hearts were reperfused and post-ischaemic coronary effluent was collected over a period of 30 s. Non-ischaemic effluent collected before ischaemia was used as a control. We investigated the effect of the effluents on cell shortening and Ca(++)-metabolism, by application of fluorescence microscopy of field-stimulated adult rat cardiomyocytes incubated with fura-2. Cells were pre-incubated with inhibitors of protein kinase A and C and with antagonists of protein kinase A-dependent prostaglandin receptors. We examined the expression of prostaglandin receptors in cardiomyocytes by Western blotting. In contrast to non-ischaemic effluent, post-ischaemic effluent induced reduction of Ca(++) transient and cell shortening in the cardiomyocytes. In contrast to protein kinase C inhibitor Myr-PKC [19-27], the protein kinase A inhibitor Rp-cAMPS completely blocked the effect of post-ischaemic effluent. Furthermore, we determined a cyclic adenosine monophosphate increase in cardiomyocytes that were pre-incubated with post-ischaemic effluent. The antagonist of prostaglandin E-receptor EP2 AH6809 and the antagonist of receptor subtype EP4 AH23848 attenuated the effect of post-ischaemic effluent in contrast to other antagonists of prostaglandin D and I receptors, which did not influence the effect. In lysates of adherend cardiomyocytes, expression of prostaglandin D, E and I receptors was detected by Western blotting. The effect of post-ischaemic effluent is mediated by the protein kinase A-dependent prostaglandin-receptor subtypes EP2 and EP4 downstream of cyclooxygenase-2.

Prostaglandins in labor - a translational approach

The mechanisms involved in the initiation of human labor are largely unknown. Understanding the molecular pathways is fundamental in both the development of effective therapeutic strategies and intervention to prevent preterm labor. Prostaglandins are bioactive lipids and members of the eicosanoids family, derived from arachidonic acid, which act in a paracrine or autocrine manner and function via binding to specific G-protein-coupled receptors, activating intracellular signaling and gene transcription. Prostaglandins have a central role in the maintenance of pregnancy and initiation of labor, with the change from uterine quiescence to a contractile state facilitated by differential expression of prostaglandin receptors within the myometrium and fetal membranes. Clinical evidence for the key role of prostaglandins in human parturition is evident from their successful exploitation as exogenous agents for the induction of labor and the role of prostaglandin synthase inhibitors as a preventative therapy for preterm labor. This review aims to focus on prostaglandin synthesis and metabolism and how differential regulation of prostaglandins and their receptors in gestational tissues interact in the initiation of labor.

An unexpected negative inotropic effect of prostaglandin F 2α in the rat heart

Prostaglandin F 2α (PGF 2α) is produced during myocardial inflammation and many of the insults that trigger contractile dysfunction also activate prostaglandin synthesis and production. However, although PGF 2α plays a significant role in the cardiac response to inflammation, the effect of this particular compound on the heart was largely studied at the cellular level and probably no due attention was paid to the effect of PGF 2α on the whole heart contractility. Therefore, in the present study we have investigated the effect of PGF 2α on isolated right ventricle of the rat heart. PGF 2α (1 nM–1 μM) induced concentration-dependent decrease of the amplitude of contractions of the ventricular muscle. Real time RT-PCR has revealed that prostaglandin FP receptors are expressed in the rat myocardium and the level of expression was similar to those of creatine kinase and adenylate kinase, which are proteins abundantly present in the heart. An antagonist of FP receptors, PGF 2α dimetilamide (10 nM), abolished negative inotropic effect induced by PGF 2α. To examine the possibility that PGF 2α could activate non-FP prostaglandin receptor, we have measured the level of expression of all known prostaglandin receptors in the rat heart. These experiments have shown that the order of expression of prostaglandin receptors in the rat heart is FP ≫ EP1 = TP > EP4 > EP3 > DP = IP. Based on the obtained results we conclude that PGF 2α induces negative inotropic effect on rat heart by activating FP prostaglandin receptors. This effect of PGF 2α could contribute to cardiac dysfunction in conditions of systemic and myocardial inflammation.

Regional Expression of Prostaglandin E2 and F2alpha Receptors in Human Myometrium, Amnion, and Choriodecidua with Advancing Gestation and Labor1

The change from uterine quiescence to enhanced contractile activity may be due to the differential expression of prostaglandin receptors within the myometrium and fetal membranes, in a temporal and topographically distinct manner. To address this question, we determined the localization and expression of the PGE2 receptor subtypes (PTGER1-4) and the PGF2alpha receptor (PTGFR) in paired upper and lower segment myometrium, amnion, and choriodecidual samples throughout human pregnancy, with and without labor. All receptor subtypes were found throughout the muscle layers in both the upper and lower uterine segments, colocalizing with alpha smooth muscle actin. A change in intracellular localization was observed at term labor, where PTGER1 and PTGER4 were predominately associated with the nucleus. Minimal changes in the expression of the PGE2 and PGF2alpha receptor subtypes were observed with gestational age, labor, or between the upper and lower myometrial segments. Receptor expression in maternal and fetal tissues differed between the receptor subtypes; PTGER1 and PTGER4 were predominately expressed in the fetal membranes, PTGER2 was greatest in the myometrium, whereas PTGER3 and PTGFR were similarly expressed in the myometrium and fetal membranes. Myometrial activation through the prostaglandin receptors is perhaps more subtle and may be mediated by a balance between one or several of the prostaglandin receptor subtypes together with other known contraction associated proteins. Lack of coordination in receptor expression between the myometrium and fetal membranes may indicate different regulatory mechanisms between these tissues, or it may suggest a function for these receptors in the amnion and choriodecidua that is independent of that seen in the myometrium.

1746: Effects of Prostaglandin E2 and Expression of Prostaglandin Receptors in Cultured Human Bladder Smooth Muscle Cells

You have accessJournal of UrologyDiscussed Poster, Wednesday, May 12, 2004, 8:00 am - 12:00 pm1 Apr 20041746: Effects of Prostaglandin E2 and Expression of Prostaglandin Receptors in Cultured Human Bladder Smooth Muscle Cells Stephen D. Confer, Theodore J. Jerdee, Frank Burks, Earl Y. Cheng, Bradley P. Kropp, and Hsueh-Kung Lin Stephen D. ConferStephen D. Confer More articles by this author , Theodore J. JerdeeTheodore J. Jerdee More articles by this author , Frank BurksFrank Burks More articles by this author , Earl Y. ChengEarl Y. Cheng More articles by this author , Bradley P. KroppBradley P. Kropp More articles by this author , and Hsueh-Kung LinHsueh-Kung Lin More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(18)38938-9AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "1746: Effects of Prostaglandin E2 and Expression of Prostaglandin Receptors in Cultured Human Bladder Smooth Muscle Cells." The Journal of Urology, 171(4S), p. 462 © 2016 by American Urological AssociationFiguresReferencesRelatedDetails Volume 171Issue 4SApril 2004Page: 462 Advertisement Copyright & Permissions© 2016 by American Urological AssociationMetricsAuthor Information Stephen D. Confer More articles by this author Theodore J. Jerdee More articles by this author Frank Burks More articles by this author Earl Y. Cheng More articles by this author Bradley P. Kropp More articles by this author Hsueh-Kung Lin More articles by this author Expand All Advertisement PDF DownloadLoading ...

283.Effects of prostaglandins on SOCS expression in T-47D breast cancer cells

There is increasing evidence to suggest that prostaglandins can upregulate suppressor-of-cytokine-signalling (SOCS) expression and so modify cellular responses to cytokines. Here we examined this possibility in two breast cancer cell lines. Initially we characterised prostaglandin receptor expression by reverse transcription-PCR, and found that T-47D cells express EP2, EP3 and EP4 receptors but not FP or EP1 receptors whereas MCF-7 cells expressed EP1 and EP4 receptors. A range of prostaglandin agonists were then used to elucidate whether prostaglandins affect SOCS expression and the receptor subtypes involved. SOCS 1-3 and CIS expression were measured by Real-Time PCR. In MCF-7 cells, PGE2 caused only minor increases in SOCS1 and SOCS3 expression. However in T-47D cells, PGE2 strongly induced SOCS3 expression with 2- and 5-fold increases in mRNA at 30 and 60 min respectively, returning to baseline at 120 min. SOCS1 was also upregulated at 30 and 60 min (3- and 5-fold respectively) and remained elevated (6-fold) at 120 min. In contrast, CIS and SOCS2 were not induced. Cloprostenol, Butaprost, Latanoprost and Sulprostone had no effect on SOCS expression, suggesting that the PGE2 response is mediated via the EP4 receptor. The induction of SOCS expression by PGE2 was not due to increased STAT3- or STAT5-tyrosine phosphorylation, and indeed we observed a decrease in STAT5 tyrosine phosphorylation 10 min and 1 h after PGE2, as determined by ip/western blotting. In summary, we propose that prostaglandin-induced SOCS1 and 3 expression in T-47Ds could constitute a means whereby cellular resistance to PRL is induced. Supported by the ARC.

Shear-induced Cyclooxygenase-2 via a JNK2/c-Jun-dependent Pathway Regulates Prostaglandin Receptor Expression in Chondrocytic Cells

Using cDNA microarrays coupled with bioinformatics tools, we elucidated a signaling cascade regulating cyclooxygenase-2 (COX-2), a pivotal pro-inflammatory enzyme expressed in rheumatic and osteoarthritic, but not normal, cartilage. Exposure of T/C-28a2 chondrocytic cells to fluid shear results in co-regulation of c-Jun N-terminal kinase2 (JNK2), c-Jun, and COX-2 as well as concomitant downstream expression of prostaglandin receptors EP2 and EP3a1. JNK2 transcript inhibition abrogated shear-induced COX-2, EP2, and EP3a1 mRNA up-regulation as well as c-Jun phosphorylation. Functional knock-out experiments using an antisense c-Jun oligonucleotide revealed the abolition of shear-induced COX-2, EP2, and EP3a1, but not JNK2, transcripts. Moreover, inhibition of COX-2 activity eliminated mRNA upregulation of EP2 and EP3a1 induced by shear. Hence, a biochemical pathway exists wherein fluid shear activates COX-2, via a JNK2/c-Jun-dependent pathway, which in turn elicits downstream EP2 and EP3a1 mRNA synthesis.