Inducible cyclooxygenase and nitric oxide synthase

Anti-inflammatory effect and mechanism of catalpol in various inflammatory diseases

Catalpol is a kind of iridoid glucoside, widely found in a variety of plants, mostly extracted from the rhizome of the traditional medicinal herb rehmanniae. It has various biological activities such as anti-inflammatory, antioxidant, and antitumor. The anti-inflammatory effects of catalpol have been demonstrated in a variety of diseases, such as neurological diseases, atherosclerosis, renal diseases, respiratory diseases, digestive diseases, bone and joint diseases, eye diseases, and periodontitis. The purpose of this review is to summarize the existing literature on the anti-inflammatory effects of catalpol in a variety of inflammatory diseases over the last decade and to focus on the anti-inflammatory mechanisms of catalpol.

Cigarette smoke is associated with up-regulation of inducible NOS and COX-2 protein expression and activity in granulosa cells of women undergoing in vitro fertilization

Cigarette smoke exposure represents a well-established ovotoxic exogenous stress, but the molecular mechanisms underlying of this effect are still unclear. Cigarette smoke upregulates inflammatory genes in the female reproductive organs, therefore an abnormal inflammation response may contribute to the impairment of female fertility. In this study we investigated for the first time the effect of cigarette smoke exposure on NOS and COX expression and activity and on their transcription factors (CREB and NF-kB) in human GCs and on the release of NO and PGE₂ in the FF in smoking and non-smoking patients undergoing IVF treatment. In addition, correlation analysis between AMH serum levels, an index of ovarian reserve, and smoking exposure or iNOS and COX-2 protein expression levels were performed using a Pearson correlation method. Cigarette smoke exposure resulted in a significant increase of iNOS and COX-2 protein expression together with an increase of iNOS activity and PGE₂ levels. pNF-kB and pCREB protein expression were upregulated in the GCs of smokers compared to non-smokers. The habit of smoking was negatively correlated with serum AMH levels, and positively correlated with iNOS and COX-2 protein expression levels. The data presented in the current study revealed a novel molecular mechanism underlying the toxic effects of cigarette smoke on fertility. Additional pathways mediating the effects of cigarette smoke exposure in human GCs cannot be excluded and should be investigated in future studies.

Cytoguardin: A Tryptophan Metabolite against Cancer Growth and Metastasis

Cytoguardin was identified in the conditioned medium of fibroblasts as a tryptophan metabolite, 5-methoxytryptophan (5-MTP). It is synthesized via two enzymatic steps: tryptophan hydroxylase (TPH) and hydroxyindole O-methyltransferase (HIOMT). A truncated HIOMT isoform, HIOMT298, catalyzes 5-MTP synthesis. Cancer cells produce scarce 5-MTP due to defective HIOMT298 expression. 5-MTP inhibits cancer cell COX-2 expression and thereby reduces COX-2-mediated cell proliferation and migration. 5-MTP also inhibits MMP-9 expression and thereby reduces cancer cell invasion. 5-MTP exerts its anti-cancer effect by blocking p38 MAPK and p38-mediated NF-κB and p300 HAT activation. The stable transfection of A549 cells with HIOMT298 restores 5-MTP production which renders cancer cells less aggressive. The implantation of HIOMT-transfected A549 into subcutaneous tissues of a murine xenograft tumor model shows that HIOMT-transduced A549 cells form smaller tumors and generate fewer metastatic lung nodules than control A549 cells. HIOMT298 transfection suppresses aromatic amino acid decarboxylase (AADC) expression and serotonin production. Serotonin is a cancer-promoting factor. By restoring 5-MTP and suppressing serotonin production, HIOMT298 overexpression converts cancer cells into less malignant phenotypes. The analysis of HIOMT expression in a human cancer tissue array showed reduced HIOMT levels in a majority of colorectal, pancreatic, and breast cancer. HIOMT298 may be a biomarker of human cancer progression. Furthermore, 5-MTP has the potential to be a lead compound in the development of new therapy for the chemoprevention of certain cancers such as hepatocellular cancer.

Astragalin attenuates oxidative stress and acute inflammatory responses in carrageenan-induced paw edema in mice

Astragalin is a flavonoid existed in several edible and medicinal plants and was recorded to have multiple biological and pharmacological significances. This work aimed to assess the possible protective effect of astragalin administration against oxidative tension, acute inflammation and histopathological deformations in a mouse paw edema model induced following intra sub-plantar injection of carrageenan. Thirty-six male Swiss mice were divided into four groups: control, carrageenan, astragalin (75 mg/kg) + carrageenan, and indomethacin (10 mg/kg) + carrageenan. Astragalin administration for five consecutive days to carrageenan injected mice showed a significant reduction in the development of paw in a time dependent effect, inhibited lipoperoxidation by-product, malondialdehyde and increased superoxide dismutase and catalase activities. Astragalin was found also to suppress the inflammatory signaling in the inflamed tissue as exhibited by the decreased myeloperoxidase activity along with the decreased protein and transcriptional level of pro-inflammatory cytokines including tumor necrosis factor-alpha, interleukin-1 beta and interleukin-6. Moreover, inducible nitric oxide synthase and cyclooxygenase-2 expressions and their products (nitric oxide and prostaglandin E2) were downregulated. Additionally, astragalin decreased monocyte chemoattractant protein-1 and nuclear factor kappa B expression in the inflamed paw tissue. The recorded findings provide evidences for the potential application of astragalin as a plant-derived remedy for the treatment of acute inflammation due to its promising antioxidant and anti-inflammatory activities along with its ameliorative impact against the histopathological changes in the paw tissue.

5-methoxytryptophan: an arsenal against vascular injury and inflammation

5-methoxytryptophan (5-MTP) is an endothelial factor with anti-inflammatory properties. It is synthesized from L-tryptophan via two enzymatic steps: tryptophan hydroxylase-1 (TPH-1) and hydroxyindole O-methyltransferase. Lipopolysaccharide (LPS) and pro-inflammatory cytokines suppress endothelial 5-MTP production by inhibiting TPH-1 expression. 5-MTP protects endothelial barrier function and promotes endothelial repair, while it blocks vascular smooth muscle cell migration and proliferation by inhibiting p38 MAPK activation. 5-MTP controls macrophage transmigration and activation by inhibiting p38 MAPK and NF-κB activation. 5-MTP administration attenuates arterial intimal hyperplasia, defends against systemic inflammation and prevents renal fibrosis in relevant murine models. Serum 5-MTP level is depressed in human sepsis as well as in mice with sepsis-like disorder. It is reduced in chronic kidney disease and acute myocardial infarction in humans. The reported data suggest that serum 5-MTP may be a theranostic biomarker. In summary, 5-MTP represents a new class of tryptophan metabolite which defends against inflammation and inflammation-mediated tissue damage and fibrosis. It may be a valuable lead compound for developing new drugs to treat complex human inflammatory disorders.

Deterioration of epithelium mediated mechanisms in diabetic-antigen sensitized airways of guinea pigs

BACKGROUND

The onset of diabetes causes disruption of respiratory epithelial mediators. The present study investigates whether diabetes modifies the epithelium mediated bronchial responses in hyper-reactive airway smooth muscle (ASM) primarily through nitric oxide (NO), cyclooxygenase (COX), and epithelium derived hyperpolarizing factor (EpDHF) pathways.

METHODS

Experimental model of guinea pigs having hyper-reactive airways with or without diabetes were developed. The responses of tracheal rings to cumulative concentrations of acetylcholine (ACh) and isoproterenol (IP) in the presence and absence of epithelium and before and after incubation with NO, K⁺_ATP and COX inhibitors, N-(ω)-Nitro-L-arginine methyl ester (L-NAME; 100 μM), glybenclamide (10 μM) and indomethacin (100 μM) were assessed.

RESULTS

In diabetic guinea pigs with hyper-reactive airways, a decrease in ACh induced bronchoconstriction was observed after epithelium removal and after incubation with L-NAME/indomethacin, suggesting damage to NO/COX pathways. Hyper-reactivity did not alter the response of trachea to ACh but affected the response to IP which was further reduced in hyper-reactive animals with diabetes. The ASM response to IP after glybenclamide treatment did not alter in hyper-reactive guinea pigs and diabetic guinea pigs with hyper-reactive airways, suggesting damage to the EpDHF pathway. Treatment with indomethacin reduced IP response in the hyper-reactive model, and did not produce any change in diabetic model with hyper-reactive airways, indicating further disruption of the COX pathway.

CONCLUSION

EpDHF pathway is damaged in hyper-reactive guinea pigs and in diabetic guinea pigs with hyper-reactive airways. Diabetes further aggravates the NO and COX mediated pathways in diabetic guinea pigs with hyper-reactive airways.

Inhibition of 5-lipoxygenase by zileuton in a rat model of myocardial infarction

OBJECTIVE

The goal of the present study was to investigate the effects of 5-lipoxygenase (5-LOX) inhibition, alone and with cyclooxygenase (COX) inhibitors, on inflammatory parameters and apoptosis in ischemia/reperfusion (I/R)-induced myocardial damage in rats. For this purpose, zileuton, a selective and potent inhibitor of 5-LOX, resulting in suppression leukotriene production, was used.

METHODS

Male Wistar rats (200-250 g; n=12 per group) were used in the study. I/R was performed by occluding the left coronary artery for 30 minutes and 2 hours of reperfusion of the heart. Experimental groups were I/R group, sham I/R group, zileuton (5 mg/kg orally, twice daily)+I/R group, zileuton+indomethacin (5 mg/kg intraperitoneally)+I/R group, zileuton+ketorolac (10 mg/kg subcutaneously)+I/R group, and zileuton+nimesulide (5 mg/kg subcutaneously)+I/R group. Following I/R, blood samples were collected to measure tumor necrosis factor alpha (TNF-α), and left ventricles were excised for evaluation of microscopic damage; malondialdehyde (MDA), glutathione, nuclear factor (NF)-κB assays; and evaluation of apoptosis.

RESULTS

Left ventricle MDA in I/R group was higher compared to sham group; however, it did not show significant change with zileuton. Although tissue injury in I/R group was less severe in all treatment groups, it was not statistically significant. NF-κB H-score and apoptotic index, which were higher in I/R group compared to sham I/R, were decreased with application of zileuton (H-score: p<0.01; apoptotic index: p<0.001). Zileuton had no significant effect on increased serum TNF-α levels in I/R group.

CONCLUSION

5-LOX inhibition in rat myocardial infarction model attenuated increased left ventricle NF-κB expression and apoptosis and these actions were not modulated by COX inhibitors.

Lumbrokinase attenuates myocardial ischemia-reperfusion injury by inhibiting TLR4 signaling

Lumbrokinase, a novel antithrombotic agent, purified from the earthworm Lumbricus rubellus, has been clinically used to treat stroke and cardiovascular diseases. However, inflammatory responses associated with the cardioprotective effect of lumbrokinase remain unknown. In this study, the signaling pathways involved in lumbrokinase-inhibited expressions of inflammation mediators were investigated in rats subjected to myocardial ischemia-reperfusion (I-R) injury. The left main coronary artery of anesthetized rats was subjected to 1h occlusion and 3h reperfusion. The animals were treated with/without lumbrokinase and the severities of I-R-induced arrhythmias and infarction were compared. Lumbrokinase inhibited I-R-induced arrhythmias and reduced mortality, as well as decreased the lactate dehydrogenase levels in carotid blood. Lumbrokinase also inhibited the enhancement of I-R induced expressions of cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), and matrix metalloproteinase (MMP)-9 through toll-like receptor 4 (TLR4) signaling pathway. Moreover, our results demonstrated that stimulation with lumbrokinase decreases the phosphorylation of JNK, IκB, and NF-κB. These findings suggested that lumbrokinase is a potent cardioprotective drug in rats with I-R injury. The cardioprotective effects of lumbrokinase may be correlated with its inhibitory effect on the I-R-induced expressions of COX-2, iNOS and MMP-9, mediated by TLR4 signaling through JNK and NF-κB pathways.

The protective effect of daidzein on high glucose-induced oxidative stress in human umbilical vein endothelial cells

Endothelial cell dysfunction is considered a major cause of vascular complications in diabetes. In the present study, we investigated the protective effect of daidzein, a natural isoflavonoid, against high-glucose-induced oxidative damage in human umbilical vein endothelial cells (HUVECs). Treatment with a high concentration of glucose (30 mM) induced oxidative stress in the endothelial cells, against which daidzein protected the cells as demonstrated by significantly increased cell viability. In addition, lipid peroxidation, intracellular reactive oxygen species (ROS) generation, and indirect nitric oxide levels induced by the high glucose treatment were significantly reduced in the presence of daidzein (0.02-0.1 mM) in a dose-dependent manner. High glucose levels induced the overexpression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and NF-κB proteins in HUVECs, which was suppressed by treatment with 0.04 mM daidzein. These findings indicate the potential of daidzein to reduce high glucose-induced oxidative stress.

A study of the mechanisms underlying the anti-inflammatory effect of ellagic acid in carrageenan-induced paw edema in rats

OBJECTIVES

Ellagic acid (EA) has shown antinociceptive and anti-inflammatory effects. Inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2) enzymes and also cytokines play a key role in many inflammatory conditions. This study was aimed to investigate the mechanisms involved in the anti-inflammatory effect of EA.

MATERIALS AND METHODS

Carrageenan-induced mouse paw edema model was used for induction of inflammation.

RESULTS

The results showed that intraplantar injection of carrageenan led to time-dependent development of peripheral inflammation, which resulted in a significant increase in the levels of tumor necrosis factor α (TNF-α) and interleukin 1 (IL-1) β, nitric oxide (NO) and prostaglandin E2 (PGE2) and also iNOS and COX-2 protein expression in inflamed paw. However, systemic administration of EA (1-30 mg/kg, intraperitoneal [i.p.]) could reduce edema in a dose-dependent fashion in inflamed rat paws with ED50 value 8.41 (5.26-14.76) mg/kg. It decreased the serum concentration of NO, PGE2, aspartate aminotransferase and alanine aminotransferase, and suppress the protein expression of iNOS, COX-2 enzymes, and attenuated the formation of PGE2, TNF-α and IL-1 β in inflamed paw tissue. We also demonstrated that EA significantly decreased the malondialdehyde (MDA) level in liver at 5 h after carrageenan injection. Moreover, histopathological studies indicated that EA significantly diminished migration of polymorphonuclear leukocytes into site of inflammation, as did indomethacin.

CONCLUSIONS

Collectively, the anti-inflammatory mechanisms of EA might be related to the decrease in the level of MDA, iNOS, and COX-2 in the edema paw via the suppression of pro-inflammatory cytokines (TNFα, IL1 β), NO and PGE2 overproduction.

Pharmacological characterization of mechanisms involved in the vasorelaxation produced by rosuvastatin in aortic rings from rats with a cafeteria-style diet

The present study aimed to investigate the possible influence of several inhibitors and blockers on the vascular effect produced by the acute in vitro application of rosuvastatin to phenylephrine-precontracted aortic rings from rats with a semi-solid, cafeteria-style (CAF) diet. It also aimed to examine the effects of rosuvastatin on the expression of endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase, constitutive cyclooxygenase, and inducible cyclooxygenase in aortic rings from rats with a CAF diet. From comparisons of the effect on phenylephrine-precontracted aortic rings extracted from rats with two different diets (a standard and a CAF diet), it was found that 10⁻⁹–10⁻⁵-mol/L rosuvastatin produced lower concentration-dependent vasorelaxation on rings from the CAF diet group. The vasorelaxant effect was unaffected by the vehicle, but it was significantly attenuated by 10⁻⁵-mol/L N^G-nitro-l-arginine methyl ester, 10⁻²-mol/L tetraethylammonium, 10⁻³-mol/L 4-aminopyridine, 10⁻⁷-mol/L apamin plus 10⁻⁷-mol/L charybdotoxin, 10⁻⁵-mol/L indomethacin, or 10⁻⁵-mol/L cycloheximide. Moreover, in aortic rings from rats with a CAF diet, rosuvastatin enhanced the expression of eNOS, inducible nitric oxide synthase, constitutive cyclooxygenase, and inducible cyclooxygenase. The acute in vitro application of rosuvastatin to phenylephrine-precontracted aortic rings from rats with a CAF diet had a vasorelaxant effect. Overall, the present results suggest that the stimulation of eNOS, the opening of Ca²⁺-activated and voltage-activated K⁺ channels, the stimulation of prostaglandin synthesis and enhanced protein levels of eNOS, inducible nitric oxide synthase, constitutive cyclooxygenase, and inducible cyclooxygenase are involved in this relaxant effect.

Smokeless tobacco consumption impedes metabolic, cellular, apoptotic and systemic stress pattern: A study on Government employees in Kolkata, India

Smokeless tobacco (SLT) remains a threat amongst a large population across the globe and particularly in India. The oral use of tobacco has been implicated to cause physiological stress leading to extreme toxicological challenge. The study included 47 SLT-users and 44 non-users providing a spectrum of pathophysiological, clinico-biochemical, antioxidant parameters, cell cycle progression study of PBMC and morphological changes of red blood cells (RBC). The expressions of p53, p21, Bax, Bcl-2, IL-6, TNF- α, Cox-2, iNOS were analyzed from thirteen representative SLT-users and twelve non-users. Difference in CRP, random glucose, serum cholesterol, TG, HLDL-C, LDL-C, VLDL-C, neutrophil count, monocyte count, ESR, SOD (PBMC) and TBARS (RBC membrane) were found to be statistically significant (p < 0.05) between the studied groups. The current study confers crucial insight into SLT mediated effects on systemic toxicity and stress. This has challenged the metabolic condition leading to a rise in the inflammatory status, increased apoptosis and RBC membrane damage. The above findings were substantiated with metabolic, clinical and biochemical parameters. This is possibly the first ever in-depth report and remains an invaluable document on the fatal effects of SLT.

Prostacyclin protects vascular integrity via PPAR/14-3-3 pathway

Vascular integrity is protected by the lining endothelial cells (ECs) through structural and molecular protective mechanisms. In response to external stresses, ECs are dynamic in producing protective molecules such as prostacyclin (PGI2). PGI2 is known to inhibit platelet aggregation and controls smooth muscle cell contraction via IP receptors. Recent studies indicate that PGI2 defends endothelial survival and protects vascular smooth muscle cell from apoptosis via peroxisome-proliferator activated receptors (PPAR). PPAR activation results in 14-3-3 upregulation. Increase in cytosolic 14-3-3ɛ or 14-3-3β enhances binding and sequestration of Akt-mediated phosphorylated Bad and reduces Bad-mediated apoptosis via the mitochondrial pathway. Experimental data indicate that administration of PGI2 analogs or augmentation of PGI2 production by gene transfer attenuates endothelial damage and organ infarction caused by ischemia-reperfusion injury. The protective effect of PGI2 is attributed in part to preserving endothelial integrity.

Pulmonary microRNA expression profiling in an immature piglet model of cardiopulmonary bypass-induced acute lung injury

After surgery performed under cardiopulmonary bypass (CPB), severe lung injury often occurs in infants. MicroRNAs (miRNAs) are potentially involved in diverse pathophysiological processes via regulation of gene expression. The objective of this study was to investigate differentially expressed miRNAs and their potential target genes in immature piglet lungs in response to CPB. Fourteen piglets aged 18.6 ± 0.5 days were equally divided into two groups that underwent sham sternotomy or CPB. The duration of aortic cross-clamping was 2 h, followed by 2 h reperfusion. Lung injury was evaluated by lung function indices, levels of cytokines, and histological changes. We applied miRNA microarray and quantitative real-time polymerase chain reaction (qRT-PCR) analysis to determine miRNA expression. Meanwhile, qRT-PCR and enzyme-linked immunosorbent assay were used for validation of predicted mRNA targets. The deterioration of lung function and histopathological changes revealed the piglets' lungs were greatly impaired due to CPB. The levels of tumor necrosis factor alpha, interleukin 6, and interleukin 10 increased in the lung tissue after CPB. Using miRNA microarray, statistically significant differences were found in the levels of 16 miRNAs in the CPB group. Up-regulation of miR-21 was verified by PCR. We also observed down-regulation in the levels of miR-127, miR-145, and miR-204, which were correlated with increases in the expression of the products of their potential target genes PIK3CG, PTGS2, ACE, and IL6R in the CPB group, suggesting a potential role for miRNA in the regulation of inflammatory response. Our results show that CPB induces severe lung injury and dynamic changes in miRNA expression in piglet lungs. Moreover, the changes in miRNA levels and target gene expression may provide a basis for understanding the pathogenesis of CPB-induced injury to immature lungs.

6,6'-bieckol isolated from Ecklonia cava protects oxidative stress through inhibiting expression of ROS and proinflammatory enzymes in high-glucose-induced human umbilical vein endothelial cells

Hyperglycemia-induced oxidative stress accelerates endothelial cell dysfunctions, which cause various complications of diabetes. The protective effects of 6,6'-bieckol (BEK), one of phlorotannin compound purified from Ecklonia cava against high-glucose-induced oxidative stress was investigated using human umbilical vein endothelial cells (HUVECs), which is susceptible to oxidative stress. High glucose (30 mM) treatment induced HUVECs' cell death, but BEK, at concentration 10 or 50 μg/ml, significantly inhibited the high-glucose-induced cytotoxicity. Furthermore, treatment with BEK dose-dependently decreased thiobarbituric acid reactive substances (TBARS), intracellular reactive oxygen species (ROS) generation, and nitric oxide level increased by high glucose. In addition, high glucose levels induced the overexpressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor-kappa B (NF-κB) proteins in HUVECs, but BEK treatment reduced the overexpressions of these proteins. These findings indicate that BEK is a potential therapeutic agent that will prevent diabetic endothelial dysfunction and related complications.

5-methoxyindole metabolites of L-tryptophan: control of COX-2 expression, inflammation and tumorigenesis

Cyclooxygenase-2(COX-2) overexpression promotes inflammation and tumorigenesis. COX-2 expression in response to diverse stimuli is tightly controlled to avoid persistent overexpression. 5-methoxyindole metabolites of L-tryptophan represent a new class of compounds that control COX-2 expression at the transcriptional level. Two of the metabolites, the newly discovered 5-methoxytryptophan (5-MTP, also known as cytoguardin) and N-acetyl 5-methoxytryptamine (melatonin) are the focus of this review. 5-MTP is produced by mesenchymal cells such as fibroblasts via 5-hydroxytryptophan (5-HTP). It inhibits COX-2 transcriptional activation induced by diverse proinflammatory and mitogenic factors. Cancer cells are deficient in cytoguardin production which contributes to COX-2 overexpression. Fibroblast-generated 5-MTP is capable of restoring the control of COX-2 overexpression in cancer cells. 5-MTP blocks cancer cell migration and invasion in vitro and inhibits tumor growth and cancer metastasis in a xenograft model. Melatonin possesses similar COX-2 suppressing and anti-cancer properties albeit at supra-pharmacological concentrations. By contrast, 5-hydroxyindole metabolites of L-tryptophan such as 5-hydroxytryptamine (serotonin), 5-hydroxytryptophol and other serotonin catabolites do not control COX-2 expression. 5-hydroxytryptophan inhibits COX-2 expression through conversion to 5-MTP. The physiological relevance of 5-MTP as an endogenous regulator of inflammation and cancer metastasis remains to be investigated. On the other hand, 5-methoxyindole metabolites of tryptophan are valuable lead compounds for development of new anti-inflammatory drugs and cancer chemoprevention.

Effect of Polyopes lancifolia Extract on Oxidative Stress in Human Umbilical Vein Endothelial Cells Induced by High Glucose

The protective effect of Polyopes lancifolia extract on high glucose-induced oxidative stress was investigated using human umbilical vein endothelial cells (HUVECs). High concentration of glucose (30 mM) treatment induced HUVECs cell death, but Polyopes lancifolia extract, at concentrations of 25, 50, and 100 μg/mL, protected cells from high glucose-induced damage. Furthermore, thiobarbituric acid reactive substances, intracellular reactive oxygen species, and nitric oxide levels increased by high glucose treatment were effectively decreased by treatment with Polyopes lancifolia extract in a dose-dependent manner. Also, Polyopes lancifolia extract treatment reduced the overexpressions of inducible nitric oxide synthase, cyclooxygenase-2, and nuclear factor-kappa B proteins activation that was induced by high glucose in HUVECs. These results indicate that Polyopes lancifolia extract is a potential therapeutic material that will reduce the damage caused by high glucose-induced-oxidative stress associated with diabetes.

Cyclooxygenase-2 expression is associated with vascular endothelial growth factor-c and lymph node metastasis in human oral tongue cancer

OBJECTIVE

This study aimed to determine the relationship of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor-c (VEGF-C) expression with lymphangiogenesis, lymph node metastasis (LNM), and other clinicopathologic features in human oral tongue cancers.

STUDY DESIGN

Forty tongue cancer specimens were immunohistochemically examined for COX-2 and VEGF-C expression and for lymphatic vessel density (LVD). We analyzed the relationships between COX-2 and VEGF-C expression and the relationships of such expression with clinicopathologic findings and survival of patients.

RESULTS

Eighteen tumors out of 40 (45%) showed COX-2 expression, and 18 tumors (45%) expressed VEGF-C. Twelve tumors (30%) coexpressed COX-2/VEGF-C. A significant correlation was found between COX-2 and VEGF-C expression (P < .01). Of note, COX-2/VEGF-C coexpression significantly correlated with lymphangiogenesis, LNM, TNM stage (P < .01), and LVD (P < .05). In Cox regression for survival, COX-2/VEGF-C coexpression was identified as an independent prognostic factor (P < .05).

CONCLUSIONS

Our results suggest that examination of immunohistochemical expression of COX-2 and VEGF-C predicts LNM and survival in human oral tongue cancers.

EGb761 inhibits inflammatory responses in human chondrocytes and shows chondroprotection in osteoarthritic rat knee

Osteoarthritis (OA) is a degenerative joint disease involving a combination of cartilage degradation and inflammation. EGb761, a standardized extract of Ginkgo biloba leaves, holds an anti-inflammatory potency. Here, we determined whether EGb761 could inhibit lipopolysaccharide (LPS)- and IL-1β-induced inflammatory responses in human articular chondrocytes and apply the chondroprotection in OA rats. We found that LPS markedly induced the productions of PGE2 and NO and the protein expressions of COX-2 and iNOS in human chondrocytes. LPS was also seen to up-regulate the expressions of toll-like receptor-4 (TLR4), its downstream signal TNF receptor-associated factor 6 (TRAF6), and nuclear factor (NF)-κB signaling. These LPS-induced inflammatory responses were efficaciously reversed by EGb761 and its active components quercetin and kampferol. The similar results could be observed by using IL-1β as an in vitro model to mimic an inflammatory response. In an OA rat model, PGE2 and NO levels in blood, the histological alterations, and COX-2 and nitrotyrosine expressions in cartilages were markedly increased, which were effectively reversed by EGb761. Our results suggested that EGb761 exerts the anti-inflammatory effects on human articular chondrocytes and OA rats.

Reciprocal regulation of the nitric oxide and cyclooxygenase pathway in pathophysiology: relevance and clinical implications

The nitric oxide (NO) and cyclooxygenase (COX) pathways share a number of similarities. Nitric oxide is the mediator generated from the NO synthase (NOS) pathway, and COX converts arachidonic acid to prostaglandins, prostacyclin, and thromboxane A(2). Two major forms of NOS and COX have been identified to date. The constitutive isoforms critically regulate several physiological states. The inducible isoforms are overexpressed during inflammation in a variety of cells, producing large amounts of NO and prostaglandins, which may underlie pathological processes. The cross-talk between the COX and NOS pathways was initially reported by Salvemini and colleagues in 1993, when they demonstrated in a series of in vitro and in vivo studies that NO activates the COX enzymes to produce increased amounts of prostaglandins. Those studies led to the concept that COX enzymes represent important endogenous "receptor" targets for amplifying or modulating the multifaceted roles of NO in physiology and pathology. Since then, numerous studies have furthered our mechanistic understanding of these interactions in pathophysiological settings and delineated potential clinical outcomes. In addition, emerging evidence suggests that the canonical nitroxidative species (NO, superoxide, and/or peroxynitrite) modulate biosynthesis of prostaglandins through non-COX-related pathways. This article provides a comprehensive state-of-the art overview in this area.

Rosuvastatin inhibits pressure-induced fibrotic responses via the expression regulation of prostacyclin and prostaglandin E2 in rat renal tubular cells

Statins are reported to alleviate renal fibrosis in animal models with ureteral obstruction. However, the molecular mechanism of this antifibrotic effect is still unclear. Pressure force is an important mechanism contributing to induction and progression of tubulointerstitial fibrogenesis in ureteric obstruction. In this study, we investigated the influence of rosuvastatin on pressure-induced fibrotic responses in rat renal tubular cells (NRK-52E). We established an in vitro pressure culture system to study pressure-induced fibrotic responses in NRK-52E cells. When NRK-52E cells were cultured in the pressure culture system, 60 mm Hg of pressure induced the expression of connective tissue growth factor (CTGF), transforming growth factor (TGF)-β, fibronectin, Smad3, and phospho-Smad3. Rosuvastatin significantly reduced these pressure-induced fibrotic responses at concentrations above 10 μM. Rosuvastatin also reduced the TGF-β-induced expression of fibronectin and CTGF in NRK-52E cells. Pretreatment with rosuvastatin significantly induced prostacyclin (PGI(2)) generation, but reduced pressure-induced prostaglandin E(2) (PGE(2)). PGI(2) synthase small interfering RNA (siRNA) transfection significantly inhibited rosuvastatin-induced peroxisome proliferator-activated receptor α activation. The blockage of peroxisome proliferator-activated receptor α by siRNA transfection reduced the inhibitory effect of rosuvastatin on pressure-induced fibrotic responses. N-[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide (NS398), a specific inhibitor of cyclooxygenase-2, diminished pressure-induced PGE(2) generation, and also reduced pressure-induced fibrotic responses. Additionally, PGE(2) decreased the antifibrotic effect of rosuvastatin. In conclusion, rosuvastatin reduces pressure-induced fibrotic responses in renal tubular cells by enhancing the PGI(2)-peroxisome proliferator-activated receptor α pathway and reducing PGE(2) generation.

Clinicopathological evaluation of cyclooxygenase-2 expression in meningioma: immunohistochemical analysis of 76 cases of low and high-grade meningioma

Tumorigenic activity of cyclooxygenase-2 (COX-2), a rate-limiting enzyme in the production of prostaglandins (PGs), has been proved for some types of cancer, including brain tumors. We evaluated expression of COX-2 in meningioma, one of the most common intracranial tumors in adults which accounts for 24-30 % of intracranial tumors. We performed immunostaining for COX-2 in 76 cases of meningioma consisting of 44 cases of low-grade (WHO Grade I) and 32 cases of high-grade (29 cases of Grade II and 3 cases of Grade III) meningioma, and evaluated COX-2 expression levels on the basis of staining intensity and proportion in tumor cells. The expression level of COX-2 in meningioma cells was significantly correlated with WHO grade (P = 0.0153). In addition, COX-2 expression was significantly correlated with MIB-1 labeling index for all 76 cases of meningioma (P = 0.0075), suggesting tumor promotion by COX-2 in meningioma progression. Our results may indicate the therapeutic value of non-steroidal anti-inflammatory drugs against meningioma, especially for patients with elevated proliferation, to regulate the tumorigenic activity of COX-2 in meningioma cells.

Quiescent fibroblasts are more active in mounting robust inflammatory responses than proliferative fibroblasts

Quiescent cells are considered to be dormant. However, recent studies suggest that quiescent fibroblasts possess active metabolic profile and certain functional characteristics. We previously observed that serum-starved quiescent fibroblasts respond to proinflammatory stimuli by robust expression of cyclooxygenase-2 (COX-2), which declines after the quiescent fibroblasts are driven to proliferation. In this study, we elucidated the underlying signaling and transcriptional mechanism and identified by microarray genes with similar differential expression. By using pharmacological inhibitors coupled with gene silencing, we uncovered the key role of protein kinase C δ (PKCδ) and extracellular signal regulated protein kinase 1/2 (ERK1/2) signaling in mediating COX-2 expression in quiescent cells. Surprisingly, COX-2 expression in proliferative cells was not blocked by PKCδ or ERK1/2 inhibitors due to intrinsic inhibition of PKCδ and ERK1/2 in proliferative cells. Restrained COX-2 transcription in proliferative cells was attributable to reduced NF-κB binding. Microarray analysis identified 35 genes whose expressions were more robust in quiescent than in proliferative cells. A majority of those genes belong to proinflammatory cytokines, chemokines, adhesive molecules and metalloproteinases, which require NF-κB for transcription. Quiescent fibroblasts had a higher migratory activity than proliferative fibroblasts as determined by the transwell assay. Selective COX-2 inhibition reduced migration which was restored by prostaglandin E(2). As COX-2 and inflammatory mediators induce DNA oxidation, we measured 8-hydroxydeoxyguanosine (8-OHdG) in quiescent vs. proliferative fibroblasts. PMA-induced 8-OHdG accumulation was significantly higher in quiescent than in proliferative fibroblasts. These findings indicate that quiescent fibroblasts (and probably other quiescent cells) are at the forefront in mounting inflammatory responses through expression of an array of proinflammatory genes via the PKCδ/ERK1/2 signaling pathway.

Control of cyclooxygenase-2 expression and tumorigenesis by endogenous 5-methoxytryptophan

Cyclooxygenase-2 (COX-2) expression is induced by mitogenic and proinflammatory factors. Its overexpression plays a causal role in inflammation and tumorigenesis. COX-2 expression is tightly regulated, but the mechanisms are largely unclear. Here we show the control of COX-2 expression by an endogenous tryptophan metabolite, 5-methoxytryptophan (5-MTP). By using comparative metabolomic analysis and enzyme-immunoassay, our results reveal that normal fibroblasts produce and release 5-MTP into the extracellular milieu whereas A549 and other cancer cells were defective in 5-MTP production. 5-MTP was synthesized from L-tryptophan via tryptophan hydroxylase-1 and hydroxyindole O-methyltransferase. 5-MTP blocked cancer cell COX-2 overexpression and suppressed A549 migration and invasion. Furthermore, i.p. infusion of 5-MTP reduced tumor growth and cancer metastasis in a murine xenograft tumor model. We conclude that 5-MTP synthesis represents a mechanism for endogenous control of COX-2 overexpression and is a valuable lead for new anti-cancer and anti-inflammatory drug development.

Redox regulation of mitochondrial function

Redox-dependent processes influence most cellular functions, such as differentiation, proliferation, and apoptosis. Mitochondria are at the center of these processes, as mitochondria both generate reactive oxygen species (ROS) that drive redox-sensitive events and respond to ROS-mediated changes in the cellular redox state. In this review, we examine the regulation of cellular ROS, their modes of production and removal, and the redox-sensitive targets that are modified by their flux. In particular, we focus on the actions of redox-sensitive targets that alter mitochondrial function and the role of these redox modifications on metabolism, mitochondrial biogenesis, receptor-mediated signaling, and apoptotic pathways. We also consider the role of mitochondria in modulating these pathways, and discuss how redox-dependent events may contribute to pathobiology by altering mitochondrial function.

Vascular reactivity in human arteries: from experimental study to clinical application

The principal function of VSM cells in mature animals is contraction. The endothelium is now recognized to elaborate various vasoactive factors and to play a critical part in regulation of vascular tone. Many circulating mediators and hormones have effects on vascular tone that are mediated via multiple receptors. Vasoactive agents also exert their effects on tissues by acting on one or more processes in the contraction–relaxation cycle in VSM. In humans,systemic, pulmonary, and various organ circulation(s) are maintained by an intricate and complex cardiovascular system. We expect future studies to clarify the sophisticated but complex mechanisms of VSM in humans.

Emerging drugs for diabetic neuropathy

IMPORTANCE OF THE FIELD

Diabetic neuropathy (DN) is a very common and disabling diabetes-related complication. DN is associated with significant morbidity and mortality. Diabetic peripheral neuropathy (DPN) can be painful in the earlier stages of the disease before becoming painless. Most of the currently available therapies are symptomatic (focusing on pain relief) rather than disease-modifying. With the exception of good glycemic control, there is currently no effective treatment to slow the progression of or reverse DPN.

AREAS COVERED IN THIS REVIEW

In this article, we review the epidemiology, pathogenesis, currently available and future treatments for DPN, and the potential development issues/challenges related to such new therapies. Literature search was performed using PubMed, Medline and Pharmaprojects from 1950 onwards. Search terms include a combination of terms such as diabetic neuropathy, pathogenesis, pathophysiology, mechanisms, treatment, therapy, oxidative/nitrosative stress, anti-oxidants, serotonin, nitrotyrosine, protein kinase C, aldose reductase, sodium channels, taurine, lipoic acid and poly (ADP-ribose) polymerase.

WHAT THE READER WILL GAIN

The reader will gain an overview of the epidemiology, clinical features and risk factors of DN. In addition, the reader will have a better understanding of the mechanisms that underpin the development of DPN and their relationships to the current and future therapies. The reader will also develop an insight into the limitations of the current approach to DPN treatment and the potential avenues for future research.

TAKE HOME MESSAGE

DN is a very common and disabling complication that currently has no effective treatments other than diabetes control. The pathogenesis of DPN is complex and multi-factorial. Several disease-modifying and symptomatic treatments are currently under development. Oxidative and nitrosative stress have been identified as key pathogenic factors in the development of DPN and new treatments target these pathways and/or their downstream consequences. Gene therapy and growth factors have also emerged as potential new therapies that target particular cellular compartments as opposed to being delivered systemically. The recognition of the difficulty in reversing established DN has focused efforts on slowing its progression.

Protective effect of diphlorethohydroxycarmalol isolated from Ishige okamurae against high glucose-induced-oxidative stress in human umbilical vein endothelial cells

In the present study, the protective effect of diphlorethohydroxycarmalol (DPHC) isolated from Ishige okamurae, a brown algae, on high glucose-induced-oxidative stress was investigated using human umbilical vein endothelial cells (HUVECs). High concentration of glucose (30 mM) treatment induced cytotoxicity whereas DPHC prevented cells from high glucose-induced damage; restoring cell viability was significantly increased. In addition, the lipid peroxidation, intracellular reactive oxygen species (ROS), and nitric oxide (NO) levels induced by high glucose treatment were effectively inhibited by addition of DPHC in a dose-dependent manner. DPHC also suppressed the over-expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins as well as nuclear factor-kappa B (NF-kappaB) activation induced by high glucose in HUVECs. These finding indicate that DPHC might be used as potential pharmaceutical agent which will reduce the damage caused by high glucose-induced-oxidative stress associated with diabetes.

Effect of mineral trioxide aggregate on rat clonal dental pulp cells: expression of cyclooxygenase-2 mRNA and inflammation-related protein via nuclear factor kappa B signaling system

INTRODUCTION

Recently, mineral trioxide aggregate (MTA) has been routinely used for endodontic treatment. It is well-known that MTA induced secondary dentin formation in pulp cavity when it was applied to dentin, whereas its cytotoxicities were unclear. The purpose of this study was to evaluate the effect of MTA on rat clonal dental pulp cells, RPC-C2A.

METHODS

This study was conducted to observe the response of RPC-C2A cells on MTA with reverse-transcriptase polymerase chain reaction, Western blot analysis, and enzyme immunoassay. Data were compared by analysis of variance. Statistical significance was established at P <.01.

RESULTS

MTA significantly caused an up-regulation of cyclooxygenase-2 (COX-2) and inducible form of nitric oxide synthase (iNOS) mRNA expression. Furthermore, MTA caused inhibitory kappa B (IkappaB) phosphorylation and translocation of nuclear factor-kappa B (NF-kappaB) subunits to nucleus. Curucumin, an inhibitor of NF-kappaB activation, suppressed MTA-induced COX-2 and iNOS mRNA expressions. In addition, MTA increased the production of prostaglandin E(2) in comparison with the controls.

CONCLUSIONS

MTA induces inflammation via NF-kappaB signaling system.

Ectopic expression of cyclooxygenase-2-induced dedifferentiation in articular chondrocytes

Cyclooxygenase-2 (COX-2) is known to modulate bone metabolism, including bone formation and resorption. Because cartilage serves as a template for endochondral bone formation and because cartilage development is initiated by the differentiation of mesenchymal cells into chondrocytes (Ahrens et al., 1977; Sandell and Adler, 1999; Solursh, 1989), it is of interest to know whether COX-2 expression affect chondrocyte differentiation. Therefore, we investigated the effects of COX-2 protein on differentiation in rabbit articular chondrocyte and chick limb bud mesenchymal cells. Overexpression of COX-2 protein was induced by the COX-2 cDNA transfection. Ectopic expression of COX-2 was sufficient to causes dedifferentiation in articular chondrocytes as determined by the expression of type II collagen via Alcian blue staining and Western blot. Also, COX-2 overexpression caused suppression of SOX-9 expression, a major transcription factor that regulates type II collagen expression, as indicated by the Western blot and RT-PCR. We further examined ectopic expression of COX-2 in chondrifying mesenchymal cells. As expected, COX-2 cDNA transfection blocked cartilage nodule formation as determined by Alcian blue staining. Our results collectively suggest that COX-2 overexpression causes dedifferentiation in articular chondrocytes and inhibits chondrogenic differentiation of mesenchymal cells.

Tomatidine inhibits iNOS and COX-2 through suppression of NF-kappaB and JNK pathways in LPS-stimulated mouse macrophages

We use the LPS-stimulated macrophage as a model of inflammation to investigate the anti-inflammatory effects of tomatidine and solasodine, whose structures resemble glucocorticoids. We found that tomatidine exhibited a more potent anti-inflammatory effect than solasodine. Tomatidine could decrease inducible nitric oxide synthase and cyclooxygenase-2 expression through suppression of I-kappaBalpha phosphorylation, NF-kappaB nuclear translocation and JNK activation, which in turn inhibits c-jun phosphorylation and Oct-2 expression. Here, we demonstrate that tomatidine acts as an anti-inflammatory agent by blocking NF-kappaB and JNK signaling, and may possibly be developed as a useful agent for the chemoprevention of cancer or inflammatory diseases.

Protective effects of cyclooxygenase-2 gene inactivation against peripheral nerve dysfunction and intraepidermal nerve fiber loss in experimental diabetes

OBJECTIVE

Activation of the cyclooxygenase (COX) pathway with secondary neurovascular deficits are implicated in the pathogenesis of experimental diabetic peripheral neuropathy (DPN). The aim of this study was to explore the interrelationships between hyperglycemia, activation of the COX-2 pathway, and oxidative stress and inflammation in mediating peripheral nerve dysfunction and whether COX-2 gene inactivation attenuates nerve fiber loss in long-term experimental diabetes.

RESEARCH DESIGN AND METHODS

Motor and sensory digital nerve conduction velocities, sciatic nerve indexes of oxidative stress, prostaglandin content, markers of inflammation, and intraepidermal nerve fiber (IENF) density were measured after 6 months in control and diabetic COX-2-deficient (COX-2(-/-)) and littermate wild-type (COX-2(+/+)) mice. The effects of a selective COX-2 inhibitor, celecoxib, on these markers were also investigated in diabetic rats.

RESULTS

Under normal conditions, there were no differences in blood glucose, peripheral nerve electrophysiology, markers of oxidative stress, inflammation, and IENF density between COX-2(+/+) and COX-2(-/-) mice. After 6 months, diabetic COX-2(+/+) mice experienced significant deterioration in nerve conduction velocities and IENF density and developed important signs of increased oxidative stress and inflammation compared with nondiabetic mice. Diabetic COX-2(-/-) mice were protected against functional and biochemical deficits of experimental DPN and against nerve fiber loss. In diabetic rats, selective COX-2 inhibition replicated this protection.

CONCLUSIONS

These data suggest that selective COX-2 inhibition may be useful for preventing or delaying DPN.

Nephrotoxicity and its prevention by taurine in tamoxifen induced oxidative stress in mice

Tamoxifen (TAM) is an anti-neoplastic drug used for the treatment of breast cancer. It decreases the hexose monophosphate shunt and thereby increasing the incidence of oxidative stress in cells leading to tissue injury. The present study was undertaken to investigate modulatory effects of taurine on the nephrotoxicity of TAM with special reference to protection against disruption of nonenzymatic and enzymatic antioxidants. Oxidative stress was measured by renal lipid peroxidation (LPO) level, protein carbonyl (PC) content, reduced glutathione (GSH), activities of phase I and II drug metabolizing and antioxidant enzymes. TAM treatment resulted in a significant (P < 0.001) increase in LPO in kidney tissues as compared to control, while taurine pretreatment showed a significant decrease (P < 0.01) in the LPO in kidneys when compared with the TAM-treated group. Taurine + TAM group animals showed restoration in the level of cytochrome P450 content, activities of glutathione metabolizing enzymes viz., glutathione-S-transferase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase. Pretreatment of animals with taurine markedly attenuated, PC content, restored the depleted nonenzymatic and enzymatic antioxidants. These results clearly demonstrate the role of oxidative stress, and suggest a protective effect of taurine on TAM-induced nephrotoxicity in mice.

Effect of a previous pregnancy on vascular function in endothelial nitric oxide synthase 3 knockout mice

OBJECTIVE

Nitric oxide deficiency has been implicated in adverse pregnancy outcomes. Mice that lack endothelial nitric oxide synthase (NOS3) have abnormal in vitro vascular reactivity. Our objective was to assess the effect of a previous pregnancy on the abnormal vascular function of NOS3 knockout mice.

STUDY DESIGN

Carotid arteries from pregnant NOS3 knockout (NOS3(-/-KO)) and wild-type control mice (NOS3(+/+WT)) from first and second pregnancy were obtained for in vitro vascular reactivity studies. Vascular responses to cumulative concentrations of the vasoconstrictors phenylephrine, serotonin, and thromboxane and the vasorelaxants acetylcholine, sodium nitroprusside, and isoproterenol were determined.

RESULTS

In the first pregnancy, contractile responses were exaggerated in the knockout animals, compared with the wild-type animals. However, the second pregnancy in knockout animals was associated with normalization of responses to phenylephrine and serotonin and increased responses to the endothelium-independent relaxants.

CONCLUSION

The vascular function of NOS3 knockout mice improves with subsequent pregnancy becoming comparable to wild-type animals.

Protective effects of vitamins C and E against endometrial damage and oxidative stress in fluoride intoxication

1. Fluoride (F) is an essential trace element that has protective effects against bone mineral loss. However, it becomes toxic at higher doses and induces some adverse effects on a number of physiological functions, including reproduction. The aims of this study were to examine F-induced oxidative stress that promotes production of reactive oxygen species (ROS) and to investigate the role of vitamins C and E against possible F-induced endometrial impairment in rats. 2. Rats were divided into three groups: control, F and F plus vitamins. The F group was given 100 mg/L orally for 60 days. Combined vitamins were also administered orally. Fluoride administration to control rats significantly increased endometrial malondialdehyde (MDA) but decreased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities. Endometrial glandular and stromal apoptosis were investigated by DNA nick end-labelling (TUNEL) method on each sample and the mean endometrial apoptotic index (AI) was calculated. 3. Vitamin administration with F treatment caused endometrial MDA to decrease, but SOD, GSH-Px and CAT activities to increase, all to significant levels. Vitamins showed a histopathological protection against F-induced endometrial damage. There was a significant difference in the AI between the groups. Lymphocyte and eosinophil infiltration in stroma in F-treated rats were more than those in the control and F + Vit groups. 4. It can be concluded that oxidative endometrial damage plays an important role in F-induced endometrial toxicity, and the modulation of oxidative stress with vitamins reduces F-induced endometrial damage both at the biochemical and histological levels.

Regression of endometrial explants in a rat model of endometriosis treated with melatonin

OBJECTIVE

To determine the antioxidant, antiinflammatory, and immunomodulatory effects of melatonin on endometrial explants, the distribution of cyclooxygenase-2 (COX-2), the activity of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and levels of malondialdehyde (MDA) in the rat endometriosis model.

DESIGN

Prospective, placebo-controlled experimental study.

SETTING

Experimental surgery laboratory in a university department.

ANIMAL(S)

Twenty-five rats with experimentally induced endometriosis.

INTERVENTION(S)

Endometriosis was surgically induced in 25 rats by transplanting an autologous fragment of endometrial tissue onto the inner surface of the abdominal wall. Four weeks later, three rats were killed and the remaining 22 rats given second-look laparotomies to identify and measure ectopic uterine tissue in three dimensions. After the second laparotomy, 4 weeks of vehicle and melatonin treatment were administered, then all of the rats were given a third laparotomy and killed.

MAIN OUTCOME MEASURE(S)

The volume and weight of the implants were measured. The remaining rats were randomly divided into two groups. In control group (group 1; n = 11) no medication was given. To the rats in melatonin-treated group (group 2; n = 11), 10 mg/kg a day of melatonin was administered intraperitoneally. Four weeks later, after the second laparotomy, the endometrial explants were reevaluated morphologically, and COX-2 expression was evaluated immunohistochemically and histologically. In addition, endometrial explants were analyzed for the antioxidant enzymes SOD, CAT, and MDA, a marker of lipid peroxidation. A scoring system was used to evaluate expression of COX-2 and preservation of epithelia.

RESULT(S)

The pretreatment and posttreatment volumes within the control group were 135.9 +/- 31.5 and 129.4 +/- 28.7, respectively. The mean explant volume was 141.4 +/- 34.4 within the melatonin group before the treatment and 42.9 +/- 14.0 after 4 weeks of treatment. There was a statistically significant difference in spherical volumes (129.4 +/- 28.7 versus 42.9 +/- 14.0 mm(3)) of explant weights (155.8 +/- 27.1 versus 49.6 +/- 19.5 mg) and COX-2 positivity (91% versus 18.1%) between groups after the third laparotomy. In the melatonin-treated group, the endometrial explant levels of MDA statistically significantly decreased and activities of SOD and CAT significantly increased when compared with the control group. The epithelia showed statistically significantly better preservation in the control group when compared with the melatonin-treated group (2.54 +/- 0.52 versus 0.63 +/- 0.50).

CONCLUSION(S)

Melatonin causes regression and atrophy of the endometriotic lesions in rats.

Interferon-gamma suppresses cyclooxygenase-2 promoter activity by inhibiting C-Jun and C/EBPbeta binding

OBJECTIVE

Cyclooxygenase-2 (COX-2) and interferon gamma (IFNgamma) are overexpressed in vascular inflammatory and atherosclerotic lesions. We postulated that IFNgamma suppresses COX-2 expression at the transcriptional level.

METHODS AND RESULTS

The effect of IFNgamma on COX-2 expression was evaluated in several types of human cells stimulated with phorbol 12-myristate 13-acetate (PMA), interleukin (IL)-1beta, or tumor necrosis factor (TNF) alpha. IFNgamma concentration-dependently inhibited COX-2 proteins and promoter activities induced by PMA or cytokines in human fibroblasts and monocytic and endothelial cells. PMA and cytokines stimulate binding of C-Jun, C-Fos, CCAAT/enhancer binding protein beta (C/EBPbeta), or NF-kappaB to their respective regulatory elements on COX-2 promoter. IFNgamma blocked C-Jun and C/EBPbeta but not C-Fos or p50 NF-kappaB binding as determined by in vitro binding assays and chromatin immunoprecipitation assay. p300 binding to COX-2 promoter was inhibited by IFNgamma in a manner comparable to C-Jun and C/EBPbeta binding.

CONCLUSIONS

IFNgamma suppresses proinflammatory mediator-induced COX-2 transcription by selective inhibition of C-Jun and C/EBPbeta DNA binding activity and p300 recruitment in human cells. Because IFNgamma is coexpressed with COX-2 in vascular lesions, it may play a role in controlling COX-2-mediated inflammatory changes.

Differential cyclooxygenase-2 transcriptional control in proliferating versus quiescent fibroblasts

Cyclooxygenase-2 (COX-2) overexpression is associated with cancer. One potential mechanism is DNA damage caused by COX-2 derived oxidants. Since DNA in proliferating cells is highly vulnerable to oxidative damage and mutation, we propose that COX-2 transactivation by exogenous stimuli is suppressed in proliferating cells compared to quiescent cells. In this review, we provide evidence for reduced COX-2 transcriptional expression in response to phorbol esters (PMA), lipopolysaccharide (LPS), interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha). Our results show that COX-2 transcription in proliferating fibroblasts is suppressed by a small molecular weight compound produced by proliferating cells. By contrast, COX-2 expression in response to exogenous stimuli is robust in quiescent cells. The quiescent cells in human body may play a primary role in mounting response to exogenous stimuli. Salicylate inhibits COX-2 transcriptional activation in quiescent cells but not in serum-driven proliferating cells by blocking C/EBPbeta DNA binding. These studies suggest that COX-2 expressions in quiescent and proliferating cells are regulated by different mechanisms. Further investigations into their transcriptional control mechanisms will have great impact on the fundamental understanding of the division of cell functions between quiescent and proliferating cells and the design of novel therapeutic strategies.

The effect of the postnatal environment on altered fetal programming of adult vascular function in mice that lack endothelial nitric oxide synthase

OBJECTIVE

The purpose of this study was to investigate vascular reactivity in heterozygous and homozygous offspring with a genetic predisposition for hypertension after postnatal cross-fostering to mothers with the opposite genetic inheritance of the NOS3 knockout allele.

STUDY DESIGN

Homozygous NOS3 knockout (C57BL/6J-NOS3(-/-KO)) and wild-type mice (NOS3(+/+WT)) were bred to obtain heterozygous litters with a paternally derived (NOS3(+/-pat)) or maternally derived (NOS3(+/-mat)) knockout allele. After delivery, heterozygous and homozygous litters were cross-fostered to a mother with the opposite NOS3 gene status. Carotid arteries were placed in a wire myograph for isometric tension recording with the use of contractile and relaxant agents. Statistical analysis with 1-way analysis of variance and Neuman-Keuls post-hoc testing was performed.

RESULTS

Increased sensitivity to phenylephrine and absent relaxation to acetylcholine in NOS3(+/-mat) was reversed with cross-fostering, and vasorelaxation to isoproterenol was increased. Contraction to calcium was increased in the cross-fostered paternally derived and wild-type litters.

CONCLUSION

Postnatal interventions may alter the adult vascular profile favorably that is the result of an abnormal intrauterine environment.