OBJECTIVETo determine the expression of E-prostanoid1 (EP(1)) and F-prostanoid (FP) receptor mRNAs in iris-ciliary bodies of the human eye using in situ hybridization.

METHODSEP(1) and FP receptor mRNAs were detected by riboprobes labeled with digoxigenin on paraffin sections of the iris-ciliary body tissue of the human eye using in situ hybridization.

RESULTSEP(1) and FP receptor mRNAs were highly expressed in blood vessels, muscles and the endothelia of the iris. EP(1) receptor hybridization signals were present in all muscle fibers of the ciliary body. Hybridization signal corresponding to FP receptor mRNA transcript was predominantly expressed in the circular muscle and in the collagenous connective tissues of the ciliary body. FP receptor mRNA was not detected in radial and longitudinal muscles.

CONCLUSIONSEP(1) and FP receptor mRNAs in human ocular tissues appear to be widely localized in the functional sites of the respective receptor agonists. Selective localization of EP(1) and FP receptor mRNAs in the circular muscles and collagenous connective tissues of the ciliary body suggests that EP(1) and FP receptors play an important role in enhancing uveoscleral outflow of aqueous humor.

Ciliary Body ; metabolism ; Humans ; In Situ Hybridization ; Iris ; metabolism ; RNA, Messenger ; analysis ; Receptors, Prostaglandin ; genetics ; Receptors, Prostaglandin E ; genetics ; Receptors, Prostaglandin E, EP1 Subtype

Prostaglandin E
Anti-Inflammatory Agents, Non-Steroidal ; Cardiovascular Diseases/drug therapy* ; Cyclooxygenase 2 ; Dinoprostone ; Humans ; Prostaglandin-E Synthases ; Receptors, Prostaglandin E

Adipose tissue is the energy storage organ of the body, and excess energy is stored in adipocytes in the form of lipid droplets. The homeostasis of adipose tissue is the basis for the body to maintain normal metabolic activity. Prostaglandin E (PGE) is an important lipid mediator in the body. It is synthesized in almost all tissues and participates in the regulation of many physiological processes such as blood pressure, glucose and lipid metabolism, and inflammation. PGE is abundant in white adipose tissue, where it is involved in the regulation of fat metabolism. PGE plays its biological role through binding to four G protein coupled receptors (prostaglandin E receptors), including EP-1, -2, -3, and -4. The EP4 subtype has been proved to play an important role in adipogenesis and adipose metabolism: it could inhibit adipogenesis while it was activated, whereas its knockout could promote lipolysis. This review summarized the relationship between EP4 and adipose metabolism, hoping to identify new targets of drug development for metabolic disorders.
Adipocytes ; Adipogenesis ; Adipose Tissue ; metabolism ; Humans ; Receptors, Prostaglandin E, EP4 Subtype ; physiology

Prostaglandin E2 (PGE2) is a cyclooxygenase metabolite of arachidonic acid. It acts as a bioactive lipid and plays an important role in regulating many biological processes. PGE2 binds to 4 different G protein-coupled receptors including prostaglandin E2 receptor subtypes EP1, EP2, EP3 and EP4. The EP4 receptor is widely expressed in most of human organs and tissues. Increasing evidence demonstrates that EP4 is essential for cardiovascular homeostasis and participates in the pathogenesis of many cardiovascular diseases. Here we summarize the role of EP4 in the regulation of cardiovascular function and discuss potential mechanisms by which EP4 is involved in the development of cardiovascular disorders with a focus on its effect on inflammation.
Cardiovascular Diseases ; physiopathology ; Cyclooxygenase 2 ; Dinoprostone ; physiology ; Humans ; Receptors, Prostaglandin E, EP4 Subtype ; physiology

BACKGROUND/AIMS: Lubiprostone, a chloride channel type 2 (ClC-2) activator, was thought to treat constipation by enhancing intestinal secretion. It has been associated with increased intestinal transit and delayed gastric emptying. Structurally similar to prostones with up to 54% prostaglandin E2 activity on prostaglandin E receptor 1 (EP1), lubiprostone may also exert EP1-mediated procontractile effect on intestinal smooth muscles. We investigated lubiprostone's effects on intestinal smooth muscle contractions and pyloric sphincter tone. METHODS: Isolated murine small intestinal (longitudinal and circular) and pyloric tissues were mounted in organ baths with modified Krebs solution for isometric recording. Basal muscle tension and response to electrical field stimulation (EFS; 2 ms pulses/10 V/6 Hz/30 sec train) were measured with lubiprostone (10(-10)-10(-5) M) +/- EP1 antagonist. Significance was established using Student t test and P < 0.05. RESULTS: Lubiprostone had no effect on the basal tension or EFS-induced contractions of longitudinal muscles. With circular muscles, lubiprostone caused a dose-dependent increase in EFS-induced contractions (2.11 +/- 0.88 to 4.43 +/- 1.38 N/g, P = 0.020) that was inhibited by pretreatment with EP1 antagonist (1.69 +/- 0.70 vs. 4.43 +/- 1.38 N/g, P = 0.030). Lubiprostone had no effect on circular muscle basal tension, but it induced a dose-dependent increase in pyloric basal tone (1.07 +/- 0.01 to 1.97 +/- 0.86 fold increase, P < 0.05) that was inhibited by EP1 antagonist. CONCLUSIONS: In mice, lubiprostone caused a dose-dependent and EP1-mediated increase in contractility of circular but not longitudinal small intestinal smooth muscles, and in basal tone of the pylorus. These findings suggest another mechanism for lubiprostone's observed clinical effects on gastrointestinal motility.
Alprostadil ; Animals ; Baths ; Chloride Channels ; Constipation ; Contracts ; Dinoprostone ; Gastric Emptying ; Gastrointestinal Motility ; Humans ; Intestinal Secretions ; Intestine, Small ; Isotonic Solutions ; Mice ; Muscle Tonus ; Muscle, Smooth ; Muscles ; Pylorus ; Receptors, Prostaglandin E ; Receptors, Prostaglandin E, EP1 Subtype ; Lubiprostone

BACKGROUND: Vitamin D is considered to exert a protective effect on various renal diseases but its underlying molecular mechanism remains poorly understood. This study aimed to determine whether paricalcitol attenuates inflammation and apoptosis during lipopolysaccharide (LPS)-induced renal proximal tubular cell injury through the prostaglandin E₂ (PGE₂) receptor EP4. METHODS: Human renal tubular epithelial (HK-2) cells were pretreated with paricalcitol (2 ng/mL) for 1 hour and exposed to LPS (1 μg/mL). The effects of paricalcitol pretreatment in relation to an EP4 blockade using AH-23848 or EP4 small interfering RNA (siRNA) were investigated. RESULTS: The expression of cyclooxygenase-2, PGE₂, and EP4 were significantly increased in LPS-exposed HK-2 cells treated with paricalcitol compared with cells exposed to LPS only. Paricalcitol prevented cell death induced by LPS exposure, and the cotreatment of AH-23848 or EP4 siRNA offset these cell-protective effects. The phosphorylation and nuclear translocation of p65 nuclear factor-kappaB (NF-κB) were decreased and the phosphorylation of Akt was increased in LPS-exposed cells with paricalcitol treatment. AH-23848 or EP4 siRNA inhibited the suppressive effects of paricalcitol on p65 NF-κB nuclear translocation and the activation of Akt. The production of proinflammatory cytokines and the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells were attenuated by paricalcitol in LPS exposed HK-2 cells. The cotreatment with an EP4 antagonist abolished these anti-inflammatory and antiapoptotic effects. CONCLUSION: EP4 plays a pivotal role in anti-inflammatory and antiapoptotic effects through Akt and NF-κB signaling after paricalcitol pretreatment in LPS-induced renal proximal tubule cell injury.
Apoptosis* ; Cell Death ; Cyclooxygenase 2 ; Cytokines ; Ergocalciferols ; Humans ; Inflammation* ; Phosphorylation ; Receptors, Prostaglandin E, EP4 Subtype ; RNA, Small Interfering ; Vitamin D

Prostaglandin (PG) E2 exerts its actions by acting on a group of G-protein-coupled receptors (GPCRs). GPCRs responding to PGE2 consist of four subtypes namely E-prostanoid 1 (EP1), E-prostanoid 2 (EP2), E-prostanoid 3 (EP3), and E-prostanoid 4 (EP4) and multiple splicing isoforms of the subtype EP3. The EP subtypes exhibit differences in signal transduction pathway, tissue localization, and regulation of expression. This molecular and biochemical heterogeneity of PGE2 receptors leads to PGE2 being the most variable prostanoid. Studies on knockout mice deficient in each EP subtype and selective agonist and antagonist have defined PGE2 actions mediated by each subtype and identified the role each EP subtype plays in various physiological and pathophysiological responses. We summarize and review PGE2 receptor research.
Animals ; Dinoprostone ; Eicosanoids ; Mice ; Mice, Knockout ; Population Characteristics ; Prostaglandins ; Protein Isoforms ; Receptors, G-Protein-Coupled ; Receptors, Prostaglandin E ; Respiratory System ; Signal Transduction

PURPOSE: The effects of PGE2 receptors (EP1, 2, 3, 4) on the proliferation of prostate cancer cells are still unclear. The degradation of the basement membrane by MMP-2, 7, 9 and TIMP-1, 2 is a critical point in tumor invasion and metastasis. We investigated the effects of PGE2 receptors concerning MMP and TIMP after the treatment of COX-2 inhibitors on prostate cancer cell-lines. MATERIALS AND METHODS: Two prostate cancer cell-lines, PC-3 and DU-145 cells were used in this study. RT-PCR were performed to detect the mRNA expression of EP1, 2, 3, 4, MMP-2, 7, 9 and TIMP-1, 2, MMP-7 was measured by ELISA after being treated with the selective EP2 agonist and EP4 agonist 10(-10), 10(-8), 10(-6) microM respectively. RESULTS: EP2, 3 and 4 mRNA were expressed in both cell-lines. After the NS-398 treatment, EP2 and EP4 mRNA expressions decreased in PC-3 cells. While only the MMP-7 mRNA expression decreased in PC-3 cells after NS-398 treatment, after NS-398 with selective EP2 agonist and EP4 agonist, MMP-7 mRNA expression increased. In PC-3 cells, selective EP2 agonist and EP4 agonist induced a significant dose-dependent increase in MMP-7 production in comparison to the NS-398 treatment group (control) in the conditioned ELISA medium. CONCLUSIONS: These results strongly suggest that COX-2, to some extent, contribute to prostate carcinogenesis at the EP2 and EP4 receptor, which could also be explained by increments of MMP-7 in PC-3 cells. Therefore, these findings show that selective EP inhibitor is useful in preventing specific disease progression in prostate cancer.
Basement Membrane ; Carcinogenesis ; Cyclooxygenase 2 Inhibitors ; Disease Progression ; Enzyme-Linked Immunosorbent Assay ; Matrix Metalloproteinase 7 ; Neoplasm Metastasis ; Prostaglandin-Endoperoxide Synthases ; Prostate ; Prostatic Neoplasms ; Receptors, Prostaglandin E ; RNA, Messenger ; Tissue Inhibitor of Metalloproteinase-1

PURPOSE: The enhanced expression of the cyclooxygenase-2 (COX-2), prostaglandin E2 receptor (EPs) and endothelin-1 (ET-1) axis is known to play a significant role in the development and progression of several malignancies. To date, little work has been done to investigate the relationships between the COX-2, EPs and ET-1 axis in prostate cancer (PC) cells. The aim of this study is to investigate the expression of preproET-1 (PPET-1), ET-1 receptor A (ET(A)R), and endothelin converting enzyme-1 (ECE-1) in the PC cell lines and to evaluate the effects of COX-2 and EPs on the expression of PPET-1, ET(A)R, and ECE-1. MATERIALS AND METHODS: Two PC cell lines, PC-3 and DU-145 cells were used for this study. By performing reverse transcription polymerase chain reaction (RT-PCR), the mRNA expressions of PPET-1, ET(A)R and ECE-1 were detected, and then the mRNA expressions of PPET-1, ET(A)R and ECE-1 were detected after being treating the cells with selective COX-2 inhibitor (NS-398), or EP2 (butaprost) and EP4 (misoprostol), which are both agonist of 10(-10), 10(-8) and 10(-6)M. RESULTS: PPET-1, ET(A)R and ECE-1 mRNA were expressed in both cell lines. After NS-398 treatment, only the PPET-1 mRNA expression was decreased at 4, 8 and 12 hours in the PC-3 cells. EP2 and EP4 agonist induced an increase for the PPET-1, ET(A)R and ECE-1 mRNA expressions, compared with the NS-398 treated group (control), in the PC-3 cells. CONCLUSIONS: ET-1/ET(A)R and ECE-1, whose expressions are increased by EP2 and EP4, may play key roles in the development and progression of PC via COX-2. A combination treatment with selective inhibitors for COX-2, EPs and ET(A)R would be novel approach to prostate cancer therapy.
Axis, Cervical Vertebra* ; Cell Line ; Cyclooxygenase 2* ; Dinoprostone* ; Endothelin-1 ; Endothelins* ; Polymerase Chain Reaction ; Prostate* ; Prostatic Neoplasms* ; Receptors, Prostaglandin E ; Reverse Transcription ; RNA, Messenger

OBJECTIVETo investigate the changes of the activity of both protein kinase A and C and the mechanisms of antipyretic action of Guizhi decoction.

METHODThe fever responses were observed after combination injection of H-89 (a selective inhibitor of PKA) and calphostin C (a selective inhibitor of PKC), and oral pretreatment of Guizhi decoction in fever rats induced by an intra-cerebroventricular (icv) injection of an EP3 agonist, and both PKA and PKC activity in hypothalamus were measured in rats pretreated with Guizhi decoction and vehicle using isotopic tracing assay.

RESULTThe rise in rat body temperature was inhibited by H-89, Calphostin C, and Guizhi decoction, moreover, pretreatment with Guizhi decoction reduced PKA activity obviously. PKC activity in model rats exhibited a tendency to drop compared with that of control group, Oral administration of Guizhi decoction in large dose inhibited the response significantly, while the low dose of Guzhi decoction has no effect on PKC.

CONCLUSIONBoth PKA and PKC may participate in the mechanism of fever induction by EP3 agonist. The decrease of PKA and PKC may contribute to the antipyretic action of Guizhi decoction, some isoenzyme of PKC may play a role in the fever production.

Analgesics, Non-Narcotic ; pharmacology ; Animals ; Cinnamomum aromaticum ; chemistry ; Cyclic AMP-Dependent Protein Kinases ; metabolism ; Dinoprostone ; analogs & derivatives ; Dose-Response Relationship, Drug ; Drug Combinations ; Drugs, Chinese Herbal ; administration & dosage ; isolation & purification ; pharmacology ; Fever ; chemically induced ; enzymology ; Hypothalamus ; enzymology ; Male ; Plants, Medicinal ; chemistry ; Protein Kinase C ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; Receptors, Prostaglandin E ; agonists ; Receptors, Prostaglandin E, EP3 Subtype