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: To investigate the degree of cyclooxygenase-2 (COX-2) protein expression in chronic hepatitis and cirrhosis. METHODS: COX-2 protein expression was evaluated in 43 cases of chronic hepatitis and 24 cases of cirrhosis using immunohistochemical techniques. The COX-2 immunohistochemical staining score was assessed using the scoring systems of Pazirandeh et al and Qiu et al. and each scoring system was based on a sum of the parameters of staining intensity and distribution. RESULTS: The mean COX-2 expression scores in chronic hepatitis and cirrhosis were 2.5 +/- 1.3 vs. 3.3 +/- 1.1 (p = 0.008), and 3.2 +/- 2.0 vs. 4.5 +/- 1.7 (p = 0.006), respectively, based on the Pazirandeh et al. and Qiu et al. scoring systems. The percentage samples of high COX-2 expression score (4 to 5) in chronic hepatitis and cirrhosis were 16.3% vs. 45.8% (p = 0.022), and 23.3% vs. 50% (p = 0.021), respectively, based on the two scoring systems. The mean COX-2 expression scores based on the severity of hepatic fibrosis scored using Ishak's modified staging system (fibrosis score 0 to 3 vs. 4 to 6) were 2.4 +/- 1.3 vs. 3.2 +/- 1.1 (p = 0.009), and 3.1 +/- 2.0 vs. 4.3 +/- 1.8 (p = 0.009), respectively, based on the two scoring systems. CONCLUSIONS: COX-2 expression was significantly higher in liver cirrhosis group than in chronic hepatitis. COX-2 expression scores according to Ishak's staging was significantly higher in the advanced fibrosis group. COX-2 may play a role in the progression of hepatic fibrosis.
Adult ; Aged ; Cyclooxygenase 2/analysis/*physiology ; Cyclooxygenase 2 Inhibitors/therapeutic use ; Disease Progression ; Female ; Hepatitis, Chronic/enzymology ; Humans ; Immunohistochemistry ; Liver Cirrhosis/drug therapy/*enzymology ; Male ; Middle Aged

OBJECTIVETo study the inhibitory effects of c9, t11-conjugated linoleic acid (c9, t11-CLA) on migration of human gastric carcinoma cell line (SGC-7901) via cyclooxygenase-2 (COX-2) pathway.

METHODSAfter inhibiting COX-2 activity by 100 micromol/L COX-2 inhibitor NS-398 in SGC-7901 cell, we treated SGC-7901 cells with c9, t11-CLA at a concentration of 200,100, 50, 25 micromol/L for 24 h, respectively. Using reconstituted basement membrane invasion, adhesion, chemotaxis assays, we detected the effect of c9, t11-CLA and COX-2 on the cell migration.

RESULTSCompared to NS-398 group, 200, 100 micromol/L c9, t11-CLA significantly suppressed SGC-7901 cells invading into the reconstituted basement membrane (F = 14.309, P = 0.000; F = 19.005, P = 0.000). 200 micromol/L c9, t11-CLA significantly inhibited SGC-7901 cells adhering to laminin, fibronectin and Matrigel (F = 3.063, P = 0.021; F = 6.692, P = 0.001; F = 11.999, P = 0.000). The chemotaxis of SGC-7901 cells and inhibitory frequency were significantly decreased in the 200 micromol/L c9, t11-CLA group (F = 1.380, P = 0.276).

CONCLUSIONc9, t11-CLA inhibits invasion, adhesion and chemotaxis of SGC-7901 cells, and the COX-2 plays an important role in the process. [ Key words]

Cell Movement ; drug effects ; physiology ; Cyclooxygenase 2 ; metabolism ; Cyclooxygenase 2 Inhibitors ; pharmacology ; Humans ; Linoleic Acid ; metabolism ; pharmacology ; Neoplasm Invasiveness ; Stomach Neoplasms ; metabolism ; pathology ; Tumor Cells, Cultured

Inducible cyclooxygenase-2 (COX-2) has received much attention because of its role in neuro-inflammation and synaptic plasticity. Even though COX-2 levels are high in healthy animals, the function of this factor in adult neurogenesis has not been clearly demonstrated. Therefore, we performed the present study to compare the effects of pharmacological and genetic inhibition of COX-2 on adult hippocampal neurogenesis. Physiological saline or the same volume containing celecoxib was administered perorally every day for 5 weeks using a feeding needle. Compared to the control, pharmacological and genetic inhibition of COX-2 reduced the appearance of nestin-immunoreactive neural stem cells, Ki67-positive nuclei, and doublecortin-immunoreactive neuroblasts in the dentate gyrus. In addition, a decrease in phosphorylated cAMP response element binding protein (pCREB) at Ser133 was observed. Compared to pharmacological inhibition, genetic inhibition of COX-2 resulted in significant reduction of neural stem cells, cell proliferation, and neuroblast differentiation as well as pCREB levels. These results suggest that COX-2 is part of the molecular machinery that regulates neural stem cells, cell proliferation, and neuroblast differentiation during adult hippocampal neurogenesis via pCREB. Additionally, genetic inhibition of COX-2 strongly reduced neural stem cell populations, cell proliferation, and neuroblast differentiation in the dentate gyrus compared to pharmacological inhibition.
Animals ; Celecoxib/*pharmacology ; Cell Differentiation/drug effects/physiology ; Cell Proliferation/drug effects/physiology ; Cyclooxygenase 2/*genetics/metabolism ; Cyclooxygenase 2 Inhibitors/*pharmacology ; Dentate Gyrus/drug effects/*physiology ; Male ; Mice ; Mice, Knockout ; Neural Stem Cells/drug effects/physiology ; Neurogenesis/drug effects

The cyclooxygenase (COX) enzyme system is the major pathway catalyzing the conversion of arachidonic acid into prostaglandins (PGs). PGs are lipid mediators implicated in a variety of physiological and pathophysiological processes in the kidney, including renal hemodynamics, body water and sodium balance, and the inflammatory injury characteristic in multiple renal diseases. Since the beginning of 1990s, it has been confirmed that COX exists in 2 isoforms, referred to as COX-1 and COX-2. Even though the 2 enzymes are similar in size and structure, COX-1 and COX-2 are regulated by different systems and have different functional roles. This review summarizes the current data on renal expression of the 2 COX isoforms and highlights mainly the role of COX-2 and PGE2 in several physiological and pathophysiological processes in the kidney.
Acute Kidney Injury ; Arachidonic Acid ; Body Water ; Cyclooxygenase 2* ; Dinoprostone* ; Hemodynamics ; Kidney* ; Physiology* ; Prostaglandin-Endoperoxide Synthases ; Prostaglandins ; Protein Isoforms ; Sodium

OBJECTIVETo study the relation between cyclooxygenase-2 (COX-2) protein expression and biologic behavior of ovarian carcinoma.

METHODSThe level of COX-2 protein expression was detected by Western Blot assay in 54 biopsy specimens from ovarian serous tumor patients and 10 normal ovarian samples.

RESULTSThe level of COX-2 protein expression and relative quantity in ovarian serous carcinoma (81.8%, 20.08 +/- 3.53) were statistically higher than those in the benign ovarian serous tumor (0, 15.04 +/- 0.12) and in the normal ovary (0, 15.33 +/- 0.60) (P < 0.05). The level of COX-2 protein expression and relative quantity in borderline ovarian serous tumor (90.0%, 20.61 +/- 3.03) were statistically higher than those in benign ovarian serous tumor and the normal ovary (P < 0.05). The level of COX-2 protein expression and relative quantity were not significantly different from ovarian serous carcinoma and borderline ovarian serous tumor (P > 0.05); as they were between the benign ovarian serous tumor and the normal ovary (P > 0.05). The level of COX-2 protein expression and relative quantity were not significantly different among different clinical stages (I + II and III + IV), different histological grades, with or without ascites or lymphatic metastasis either.

CONCLUSIONCOX-2 overexpression may be significantly related to the oncogenesis and development of ovarian serous carcinoma, which may be an early diagnostic parameter and, hence, an attractive target for chemopreventive strategy in the treatment of ovarian serous carcinoma.

Adult ; Aged ; Blotting, Western ; Cyclooxygenase 2 ; analysis ; genetics ; physiology ; Female ; Humans ; Middle Aged ; Ovarian Neoplasms ; enzymology ; etiology

Different from the previous knowledge regarding reactive oxygen species (ROS), recent research suggests that ROS play essential roles in initiating cascade reaction of wound healing. During wound healing, ROS can serve as the second messenger to regulate signal transduction and gene expression. In this paper, we review the mechanism of generation of cyclooxygenase 2-prostaglandin E2 induced by ROS, which regulates the early inflammatory response and subsequent healing after injury.
Cyclooxygenase 2 ; metabolism ; Dinoprostone ; metabolism ; Reactive Oxygen Species ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; methods ; Signal Transduction ; Wound Healing ; physiology

OBJECTIVESTo study the role of cyclooxygenase 2 (COX 2) and prostaglandin I2 (PGI2) in the development of portal hypertensive gastropathy (PHG).

METHODSForty Wistar rats were divided into surgery group (32) and control group (8). Partial portal vein ligation method was used to narrow the sectional area of portal vein to establish the experimental model of PHG in surgery group rats. Then they were divided into four groups (8 rats in each). The free pressure of portal vein was determined at the 1st, 2nd, 3rd, 4th weeks after the operation, and 8 rats were killed to observe the pathological change of gastric mucosa. The levels of 6-keto-PGF1 alpha, a stable metabolite of PGI2, were determined by radioimmunoassay in gastric mucosa homogenate and the blood of portal vein. The expression of COX 2 in gastric mucosa was determined by immunohistochemistry.

RESULTSThe free pressure of portal vein increased rapidly after partial portal vein ligation and maintained a high stable level after 1 week. They were (2.40+/-0.15) kPa, (2.38+/-0.17) kPa, (2.52+/-0.21) kPa, and (2.46+/-0.17) kPa at the 1st, 2nd, 3rd, and 4th weeks after partial portal vein ligation, while it was (0.90+/-0.16) kPa in control group (t>or=17.356, P<0.05). The gastric mucosa appeared pale, edema, hyperaemia, surface erosion, punctate hemorrhage and these lesions were more apparent with the time after the operation. The pathological examination showed that the gastric mucosa and submucosa thickened. The vessels of gastric mucosa and submucosa expanded and increased. There were lymphocytes and neutrophils infiltration around the vessels in the gastric mucosa and submucosa. The 6-keto-PGF1 alpha levels in gastric mucosa and the blood of portal vein increased rapidly and maintained a high level after partial portal vein ligation,which were higher than those in control group (104.52pg/ml+/-25.11pg/ml vs 73.62pg/ml+/- 20.33pg/ml, t=2.710, P<0.05; 180.21pg /ml+/-37.56pg /ml vs 142.11pg /ml+/-31.51pg /ml, t=2.198, P<0.05). The results of immunohistochemistry showed that the intensity and degree of the COX 2 staining in gastric tissue increased at the 1st, 2nd, 3rd, 4th weeks after partial portal vein ligation, while the COX 2 in control group rats was negative.

CONCLUSIONSThe expression of COX 2 and PGI2 in gastric tissue increased in portal hypertension. PGI2 as an inflammatory medium, damages the gastric mucosa by expanding vessels and other mechanisms in portal hypertension. It may be one of the important factors contributing to the development of PHG.

Animals ; Cyclooxygenase 2 ; Disease Models, Animal ; Epoprostenol ; physiology ; Hypertension, Portal ; complications ; pathology ; Isoenzymes ; physiology ; Male ; Prostaglandin-Endoperoxide Synthases ; physiology ; Rats ; Rats, Wistar ; Stomach Diseases ; etiology ; pathology

BACKGROUNDCigarette smoking has been verified as the risk factor of esophageal squamous cell carcinoma (ESCC). Overexpression of cyclooxygenase 2 (COX-2) is shown in ESCC. The objective of this study was to investigate the effects of cigarette smoking ethanol extract (EE) on the proliferation of the human ESCC cell lines, and to explore the correlation between the proliferation rate of human ESCC cell lines and the expression pattern of COX-2. Whether aspirin can inhibit the proliferation of the ESCC cell lines pretreated with EE, and regulate the mRNA expression levels of COX-2 are also examined.

METHODSTwo human ESCC cell lines were selected. EC109 was poorly differentiated and EC9706 was highly differentiated. EC109 and EC9706 were treated with EE and aspirin for different time course. The cell growth of ESCC was measured by MTT reduction assay and the expression of COX-2 was measured by RT-PCR and Western blot analysis.

RESULTSEE promoted the proliferation of EC109 and EC9706 in dose- and time-dependent manners. In the concentration range (10 - 100 microg/ml for EE) and in the time range (24 - 72 hours) after addition of EE, the cell proliferation was prominent in an up-scaled manner respectively. Aspirin could inhibit the proliferation of cell lines EC109 and EC9706, pretreated with EE for 5 hours, in a dose-dependent manner. In the concentration range (0.5 - 8.0 mmol/L for aspirin), the cell growth inhibition was prominent in an up-scaled manner accordingly (P < 0.05). The effect of EE on cell proliferation was correlated with the up-regulation of COX-2 gene. However, the cell growth inhibition of aspirin was correlated with the down-regulation of COX-2 gene.

CONCLUSIONSEE can stimulate the proliferation of human ESCC cell lines EC109 and EC9706, most likely through up-regulating the expression of COX-2. Aspirin can inhibit the proliferation of ESCC cell lines induced by EE, which suggests it may be advantageous in the chemoprevention and therapy of human tobacco-related ESCC. And its effect is likely to be related with modulating COX-2 activity.

Aspirin ; pharmacology ; Carcinoma, Squamous Cell ; drug therapy ; etiology ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclooxygenase 2 ; physiology ; Cyclooxygenase 2 Inhibitors ; pharmacology ; Esophageal Neoplasms ; drug therapy ; etiology ; pathology ; Humans ; Smoking ; adverse effects

BACKGROUNDCyclooxygenase (COX) is the rate-limiting enzyme in the production of prostanoids from arachidonic acid. COX-2 is the inducible enzyme in the COX family, together with the prostanoids forms the COX-2/prostanoid pathway. Research showed that the COX-2/prostanoid pathway is activated in hepatic diseases and liver stress reaction, such as fibrogenesis, portal hypertension, carcinogenesis, and ischemic/reperfusion injury. But there was no report on visceral pain induced liver stress. This study was to investigate the role of the COX-2/prostanoid pathway in liver stress response in rat acute colitis visceral pain liver stress model.

METHODSFifty-three male SD rats were randomly divided into Naive, Model, NS398 treatment, and Morphine treatment groups. The rat acute colitis visceral pain liver stress model was established under anesthesia by the colonic administration of 0.5 ml of 6% acetic acid using a urethral catheter. NS398 and morphine were administrated 30 minutes prior to model establishment in NS398 and Morphine treatment groups respectively. Spontaneous activities and pain behavior were counted and the extent of colonic inflammation was assessed histologically. Liver tissue levels of Glutathione-S-Transferase (GST) activity, COX-2 mRNA, prostaglandin E2 (PGE2), thromboxane B2 (TXB2) and 6-Ketone-prostaglandin F1alpha (6-K-PGF1alpha) contents were assessed.

RESULTSThirty minutes after the colonic administration of acetic acid, a significant decrease in spontaneous activities and an increase in pain behaviors were observed in Model group (P < 0.01 and P < 0.05 respectively), accompanied by colonic inflammation. Liver GST activity levels significantly dropped (P < 0.05). Liver COX-2 mRNA expression significantly increased, accompanied by an increase in liver concentrations of PGE2 and TXB2, but no obvious change in 6-K-PGF1alpha concentrations. NS398 and morphine both ameliorated post-stress liver GST activity (P < 0.05 and P < 0.01 respectively), decreased stress-induced COX-2 expression, decreased PGE2 and TXB2 production, but increased liver 6-K-PGF1alpha levels. Morphine attenuation in colonic tissue inflammation was apparent at 24 hours (P < 0.05).

CONCLUSIONSAcute colitis visceral pain liver stress can induce liver injury. Liver injury might have occurred through the activation of the COX-2/prostanoid pathway and increased production of PGE2 and TXB2. Effective analgesia might offer protective effect during visceral pain stress.

Acute Disease ; Animals ; Colitis ; physiopathology ; Cyclooxygenase 2 ; physiology ; Hyperalgesia ; physiopathology ; Liver ; metabolism ; Liver Diseases ; physiopathology ; Male ; Morphine ; pharmacology ; Nitrobenzenes ; pharmacology ; Prostaglandins ; physiology ; Rats ; Rats, Sprague-Dawley ; Sulfonamides ; pharmacology