Prostanoid Synthesis Research Articles

Acute and chronic role of nitric oxide, renin-angiotensin system and sympathetic nervous system in the modulation of calcium sensitization in Wistar rats.

Principal vasoactive systems - renin-angiotensin system (RAS), sympathetic nervous system (SNS), nitric oxide (NO) and prostanoids - exert their vascular effects through the changes in calcium levels and/or calcium sensitization. To estimate a possible modulation of calcium sensitization by the above vasoactive systems, we studied the influence of acute and chronic blockade of particular vasoactive systems on blood pressure (BP) changes elicited in conscious normotensive rats by acute dose-dependent administration of Rho-kinase inhibitor fasudil. Adult male chronically cannulated Wistar rats were used throughout this study. The acute inhibition of NO synthase (NOS) by L-NAME enhanced BP response to fasudil, the effect being considerably augmented in rats deprived of endogenous SNS. The acute inhibition of prostanoid synthesis by indomethacin modified BP response to fasudil less than the acute NOS inhibition. The chronic NOS inhibition caused moderate BP elevation and a more pronounced augmentation of fasudil-induced BP changes compared to the effect of acute NOS inhibition. This indicates both short-term and long-term NO-dependent attenuation of calcium sensitization. Long-term inhibition of RAS by captopril caused a significant attenuation of BP changes elicited by fasudil. In contrast, a long-term attenuation of SNS by chronic guanethidine treatment (in youth or adulthood) had no effect on BP response to fasudil, suggesting the absence of SNS does not affect calcium sensitization in vascular smooth muscle of normotensive rats. In conclusion, renin-angiotensin system contributes to the long-term increase of calcium sensitization and its effect is counterbalanced by nitric oxide which decreases calcium sensitization in Wistar rats.

Epigenetics override pro-inflammatory PTGS transcriptomic signature towards selective hyperactivation of PGE2 in colorectal cancer.

BackgroundMisregulation of the PTGS (prostaglandin endoperoxide synthase, also known as cyclooxygenase or COX) pathway may lead to the accumulation of pro-inflammatory signals, which constitutes a hallmark of cancer. To get insight into the role of this signaling pathway in colorectal cancer (CRC), we have characterized the transcriptional and epigenetic landscapes of the PTGS pathway genes in normal and cancer cells.ResultsData from four independent series of CRC patients (502 tumors including adenomas and carcinomas and 222 adjacent normal tissues) and two series of colon mucosae from 69 healthy donors have been included in the study. Gene expression was analyzed by real-time PCR and Affymetrix U219 arrays. DNA methylation was analyzed by bisulfite sequencing, dissociation curves, and HumanMethylation450K arrays. Most CRC patients show selective transcriptional deregulation of the enzymes involved in the synthesis of prostanoids and their receptors in both tumor and its adjacent mucosa. DNA methylation alterations exclusively affect the tumor tissue (both adenomas and carcinomas), redirecting the transcriptional deregulation to activation of prostaglandin E2 (PGE2) function and blockade of other biologically active prostaglandins. In particular, PTGIS, PTGER3, PTGFR, and AKR1B1 were hypermethylated in more than 40 % of all analyzed tumors.ConclusionsThe transcriptional and epigenetic profiling of the PTGS pathway provides important clues on the biology of the tumor and its microenvironment. This analysis renders candidate markers with potential clinical applicability in risk assessment and early diagnosis and for the design of new therapeutic strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13148-015-0110-4) contains supplementary material, which is available to authorized users.

Cyclooxygeanse-2 promotes metastasis in osteosarcoma.

Cyclooxygenase-2 (COX-2), an inducible form of the enzyme that catalyzes the first step in the synthesis of prostanoids, is associated with carcinogenesis, which is suspected to promote angiogenesis and tissue invasion of tumors and resistance to apoptosis. COX-2 is also involved in metastasis and poor prognosis of cancer. Osteosarcoma with COX-2 positivity is from 67 to 92 %. COX-2-positive rate in metastatic lesions was greater than that of biopsy and/or resected samples of the primary site in osteosarcoma. And, what role does COX-2 play in osteosarcoma metastasis? Genetic studies support a cause-effect connection between COX-2 and tumorigenesis. COX-2 expression had a poor prognosis with regard to metastasis, and patients with increased COX-2 expression in lung metastases died of the disease. COX-2 expression has also been established as a marker in human osteosarcoma, and COX-2 inhibition has been suggested as a possible way of improving therapeutic outcome. In addition, COX-inhibitors inhibit the tumor initiation, matrix metalloproteinases (MMPs), cell differentiation and T cell proliferation and suppression of the antitumor activity of natural killer cells and macrophages, angiogenic mechanism. Therefore, we can exert the COX-inhibitors to potentialize the effects of chemotherapeutic agents, and reverse the metastasis in osteosarcoma to facilitate the patient who may benefit from addition of COX-inhibitors to standard cytotoxic therapy.

The negative regulatory role of ORMDL3 in antigen-induced cytokine production, cyclooxygenase-2 expression, and chemotactic response in mast cells (IRM11P.637)

Abstract Single-nucleotide polymorphism studies have linked the chromosome 17q12-q21 region, where human ORMDL3 gene is localized, to the risk of asthma and other inflammatory diseases. Although mast cells are involved in development of these diseases, the contribution of ORMDL3 to mast cell physiology is unknown. In this study we examined the role of ORMDL3 in mouse bone marrow-derived mast cells with reduced or enhanced ORMDL3 expression. Our data show that in antigen-activated mast cells, reduced expression of the ORMDL3 protein had no effect on degranulation, calcium response, and sarco/endoplasmic reticulum Ca2+ ATPase 2b expression, but significantly enhanced phosphorylation of the IκBα and translocation of the NF-κB p65 subunit into the nucleus. These events were followed by an increased expression of pro-inflammatory cytokines (TNF-α, IL-6, and IL-13), chemokines (CCL3 and CCL4), and cyclooxygenase-2, an enzyme involved in the synthesis of prostanoids. Antigen-mediated chemotaxis was also enhanced in ORMDL3-deficient cells, whereas adhesion and spreading on fibronectin were decreased. On the other hand, increased expression of ORMDL3 had no significant effect on mast cell signaling events, except for reduced antigen-mediated chemotaxis. Our data provide the evidence that ORMDL3 in mast cells acts as a non-inducible suppressor of NF-kB-directed signaling pathways and chemotaxis.

Effect of the types of dietary fats and non-dietary oils on bone metabolism

ABSTRACTNutrients beyond calcium and vitamin D have a role on bone health, and in treatment and prevention of osteoporosis. Quality and quantity of dietary fat may have consequences on skeletal health. Diets with highly saturated fat content produce deleterious effects on bone mineralization in growing animals. Conversely, dietary n-3-long chain polyunsaturated fatty acids play an important role in bone metabolism and may help in prevention and treatment of bone disease. Some reports suggest a correlation between the dietary ratio of n-6 and n-3 polyunsaturated fatty acids and bone formation. Specific dietary fatty acids were found to modulate prostanoid synthesis in bone tissue and improve bone formation in both animal and clinical trials. The skeletal benefits of dietary isoprenoids are extremely documented. Higher isoprenoids intake may relate to higher bone mineral density. Dietary supplements containing fish oil, individual polyunsaturated fatty acids, and isoprenoids could be used as adjuvant with bone medications in osteoportic conditions but their doses must be considered to avoid detrimental effect of over dosages.

Enhancement on reactive oxygen species and COX-1 mRNA levels modulate the vascular relaxation induced by sodium nitroprusside in denuded mice aorta.

This study aimed to investigate the modulation of nitric oxide/reactive oxygen species in sodium nitroprusside relaxation in mice aorta. Sodium nitroprusside induced relaxation in endothelium-intact (e+) and endothelium-denuded (e-) aortas with greater potency in e+ than in e-. The nitric oxide synthase inhibitor did not alter the sodium nitroprusside relaxation in both e+ and e- aortas. However, the superoxide anion scavenger abolished the difference in sodium nitroprusside potency between e+ and e-. Sodium nitroprusside reduced dihydroethidium-derived fluorescent products in both groups; however, the difference between intact and denuded mice aorta remains. The glutathione levels and basal antioxidant activity of superoxide dismutase were reduced in e- aorta when compared with e+, and these values were not altered by sodium nitroprusside. Confirming these results, the levels of lipid peroxidation in e+ were significantly lower when compared to e-, and these values were not altered by sodium nitroprusside. The sodium nitroprusside potency in the presence of a nonselective COX inhibitor or the EP/DP prostaglandin receptor antagonist in endothelium denuded was similar to that in intact mice aorta. Based on these results, we performed the COX-1 and COX-2 mRNA level studies, and in denuded mice aorta, there was an upregulation in COX-1 mRNA levels. Taken together, our findings show that in the absence of endothelium, there is an enhancement of superoxide levels, leading to GSH consumption and higher levels of lipid peroxidation, showing an intense redox status. Furthermore, in denuded mice aorta, there was an upregulation of COX-1 mRNA expression, leading to vasoconstrictor prostanoids synthesis. The interaction of vasoconstrictor prostanoids with its receptors EP/DP negatively modulates the vascular relaxation induced by SNP in denuded mice aorta.

Synthesis and the absolute configuration of both enantiomers of 4,5-dihydroxy-3-(formyl)cyclopent-2-enone acetonide as a new chiral building block for prostanoid synthesis.

The synthesis of both enantiomers of 4,5-dihydroxy-3-(formyl)cyclopent-2-enone acetonide (5) was accomplished in five steps starting from meso-tartaric acid (6). The key steps involved are preparation of the isopropylidene protected 3-[(dimethoxyphosphoryl)methyl]-4,5-dihydroxycyclopent-2-enone (9), resolution of the diastereoisomeric products 10 of the Horner reaction of racemic 9 with (R)-glyceraldehyde acetonide and the final regioselective ozonolysis of the exocyclic carbon–carbon double bond of the separated dienones 10 leading to both enantiomeric title compounds 5. The absolute configuration of both enantiomers was initially assigned based on the comparison of the chiroptical properties obtained from the DFT calculations with the experimental data and finally confirmed by X-ray analysis.

Cyclooxygenase pathways.

This review compiles the current knowledge on the effects of prostanoids - arachidonic acid metabolites - on their own synthesis, activity and degradation. Interaction mechanisms between the receptors for the relevant compounds are presented, in particular with regard to the cooperation between a thromboxane A₂ and prostaglandin I₂ receptors. The questions of desensitization and internalization of receptors are discussed. The stages of the inflammatory response and tumor progression are analyzed against the background of the disruption of the synthesis of prostanoids. Special attention is given to the significance of 15-deoxy-Δ(12,14)-prostaglandin J₂ in the regulation of the synthesis of prostanoids and its role as an anti-inflammatory agent. Ultimately, therapeutic approaches as used in various treatments are discussed in the light of the available knowledge.

Nano-LC-MS/MS for the quantitation of prostanoids in immune cells.

Prostanoids, derivatives of arachidonic acid, are involved in inflammation and immune reactions. To understand the role of prostanoids produced by diverse immune cells, a highly sensitive quantitation method for prostaglandin E2 (PGE2), prostaglandin D2 (PGD2), 6-keto prostaglandin F1α (6-keto PGF1α), prostaglandin F2α (PGF2α), and thromboxane B2 (TXB2) by means of nano-liquid chromatography-tandem mass spectrometry has been developed. It was validated according to the guidelines of the Food and Drug Administration (FDA) in terms of linearity, precision, accuracy, recovery, stability, and lower limit of quantitation (LLOQ). The LLOQ were 25pg/mL in the injected solution (75fg on column (o.c.)) for PGE2 and PGD2 and 37.5pg/mL (112.5fg on column) for 6-keto PGF1α, PGF2α, and TXB2, respectively. It was successfully applied to murine mast cells isolated from paws after zymosan injection and to CD4(+) and CD8(+) T lymphocytes from blood of sensitized versus non-sensitized mice in context of a delayed type hypersensitivity model. About 5,000 (T cells) to 40,000 (mast cells) cells were sufficient for quantitation. In the mast cells, the production of PGE2 increased at a significantly higher extent than the synthesis of the other prostanoids. The T lymphocytes did not show any difference in prostanoid production, no matterwhether they were obtained from sensitized mice or non-sensitized mice.

Sex differences in endothelial function in porcine coronary arteries: a role for H2O2 and gap junctions?

Cardiovascular risk is higher in men and postmenopausal women compared with premenopausal women. This may be due to sex differences in endothelial function. Here, sex differences in endothelial function of porcine coronary arteries (PCAs) were investigated. Distal PCAs were studied under myographic conditions and after precontraction with U46619. Concentration-response curves to bradykinin were constructed in the presence of a range of inhibitors. In male and female PCAs, bradykinin produced comparable vasorelaxant responses. Inhibition of NO and prostanoid synthesis produced greater inhibition in males compared with females. Removing H2 O2 with PEG-catalase reduced the maximum relaxation in the absence, but not the presence of L-NAME and indomethacin in females, and had no effect in males. Blocking gap junctions with 100 µM carbenoxolone or 18α-glycyrrhetinic acid further inhibited the endothelium-derived hyperpolarization (EDH)-mediated response in females but not in males. In female PCAs, the maximum EDH-mediated response was reduced by inhibiting SKCa with apamin and by inhibiting IKCa with TRAM-34, or with both. In male PCAs, at maximum bradykinin concentration, the EDH-mediated response was reduced in the presence of apamin but not TRAM-34. Western blot did not detect any differences in connexins 40 or 43 or in IKCa expression between male and female PCAs. H2 O2 mediated some part of endothelium-dependent vasorelaxation in female PCAs and EDH was more important in females, with differences in the contribution of gap junctions and IKCa channels. These findings may contribute to understanding vascular protection in premenopausal women.

Diversity and function of membrane glycerophospholipids generated by the remodeling pathway in mammalian cells

Cellular membranes are composed of numerous kinds of glycerophospholipids with different combinations of polar heads at the sn-3 position and acyl moieties at the sn-1 and sn-2 positions, respectively. The glycerophospholipid compositions of different cell types, organelles, and inner/outer plasma membrane leaflets are quite diverse. The acyl moieties of glycerophospholipids synthesized in the de novo pathway are subsequently remodeled by the action of phospholipases and lysophospholipid acyltransferases. This remodeling cycle contributes to the generation of membrane glycerophospholipid diversity and the production of lipid mediators such as fatty acid derivatives and lysophospholipids. Furthermore, specific glycerophospholipid transporters are also important to organize a unique glycerophospholipid composition in each organelle. Recent progress in this field contributes to understanding how and why membrane glycerophospholipid diversity is organized and maintained.

Beneficial effects of cocoa on lipid peroxidation and inflammatory markers in type 2 diabetic patients and investigation of probable interactions of cocoa active ingredients with prostaglandin synthase-2 (PTGS-2/COX-2) using virtual analysis

Background and aimAltered glucose metabolism, oxidative stress, lipid levels and inflammatory markers are important risk factors in diabetes, cardiovascular, and many other diseases. Cocoa has been shown to exert antioxidant and anti-inflammatory effects. The aim of this study is twofold: to assess the effect of Cocoa on the lipid profile and peroxidation in addition to the inflammatory markers in type 2 diabetic patients, and to represent a virtual model of probable action mechanism of observed clinical effects of Cocoa consumption using in silico analysis and bioinformatics data.MethodsOne hundred subjects with type 2 diabetes were included in a randomized clinical control trial. Fifty treatment subjects received 10 grams cocoa powder and 10 grams milk powder dissolved in 250 ml of boiling water, and the other fifty control subjects received only 10 grams milk powder dissolved in 250 ml boiling water. Both groups were on the mentioned regimen twice daily for 6 weeks. Blood samples were obtained prior to Cocoa consumption and 6 weeks after intervention. Serum lipids and lipoproteins profile, malondialdehyde and inflammatory markers including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and high sensitive C-reactive protein (hs-CRP) were measured. For statistical analysis two independent and paired samples t-test and linear regression were used. Bioinformatics and virtual analysis were performed using string data base and Molegro virtual software.ResultsCocoa consumption lowered blood cholesterol,triglyceride, LDL-cholesterol, and TNF-α, hs-CRP, IL-6 significantly (P < 0.01). The results showed that the levels of HDL-cholesterol decreased significantly (P < 0.05) but Cocoa inhibited lipid peroxidation in treatment group than control group (P < 0.0001). Virtual analysis showed that the most frequent Cocoa ingredients, (+)-Catechin and (−)-Epicatechin, can dock to the enzyme COX-2.ConclusionThese data support the beneficial effect of Cocoa on the lipid peroxidation prevention and inflammatory markers in type 2 diabetic patients. Cocoa ingredients block the Cox-2 activation and reduce inflammatory prostanoids synthesis according to virtual analysis.

Dietary energy source largely affects tissue fatty acid composition but has minor influence on gene transcription in Iberian pigs1

A trial was performed to compare the effects of different dietary sources of MUFA on the fatty acid (FA) composition, lipid metabolism, and gene transcription in different tissues of Iberian pigs. Twenty-seven Iberian male pigs of 28 kg live weight (LW) were divided in 2 groups and fed with 1 of 2 isocaloric diets: a standard diet with carbohydrates as energy source (CH) and a diet enriched with high-oleic sunflower oil (HO). Ham adipose tissue was sampled by biopsy at 44 and 70 kg LW. At 110 kg LW pigs were slaughtered and backfat, loin, and liver tissues were sampled. Animals of the HO group showed higher MUFA content and lower SFA in all the analyzed tissues (P < 0.001). These main effects were established early during the treatment and increased only slightly along time. Small diet effects were also detected on PUFA, which showed differences according to sampling time, tissue, and lipid fraction. Effects of diet on gene expression were explored with a combined approach analyzing adipose tissue transcriptome and quantifying the expression of a panel of key genes implicated in lipogenesis and lipid metabolism processes in backfat, muscle, and liver. Backfat transcriptome showed small effects of diet on gene expression, in number and magnitude. According to the posterior probabilities (PP) of the probe-specific expression differences between dietary groups (PP < 0.01), 37 genes were considered differentially expressed (DE). Gene ontology allowed relating them with several biological functions including lipid metabolic processes. Quantitative PCR confirmed several DE genes in adipose tissue (RXRG, LEP, and ME1; P < 0.0001, P < 0.05, and P < 0.0001, respectively), but no DE gene was found in loin or liver tissues. Joint results agree with a metabolic adjustment of adipose tissue FA levels by the subtle effect of the diet on the regulation of several lipid metabolism pathways, mainly FA oxidation and prostanoid synthesis, with LEP, RXRG, and PTGS2 genes playing mayor roles.

Clarification of Molecular Targets of Dioxin Toxicity

Health effects associated with exposure to various chemicals have been extensively studied. However, in most cases, the molecular basis of the underlying mechanism has been elusive. Dioxin toxicity, which has raised a significant concern in society, was discovered to be mediated by a high-affinity receptor, aryl hydrocarbon receptor (AhR), more than three decades ago. This receptor has been established to be essential for the manifestation of various toxicities, such as carcinogenicity, reproductive toxicity, developmental neurotoxicity, and immunotoxicity. However, it has not been clarified how AhR mediates such a wide variety of dioxin toxicities through AhR-dependent mechanisms. In recent years, several lines of experimental evidence have provided clues for opening the "black box" that contains the molecular mechanisms of dioxin action. In this review, I focus on dioxin toxicity phenotypes for which downstream molecular targets have begun to be elucidated. The toxicity phenotypes include impaired prostate development and hydronephrosis in mouse fetuses and pups, respectively, as well as abnormality in organogenesis in zebrafish embryos and adults. As the molecular basis of the tissue-specific endpoints of dioxin toxicity, dysregulation of AhR downstream pathways, such as signaling of prostanoid synthesis, Wnt/β-catenin signaling, and signaling by receptors for inflammatory cytokines, are discussed. The new findings on the molecular targets of dioxin may provide clues to the prospective discovery of new molecular events associated with the growth and development of organs and pathogenesis of diseases.

Computer aided design and molecular docking study of 1-n-substituted-3, 5-diphenyl-2-pyrazoline derivatives as cox–2 inhibitors.

Cyclooxygenase (COX) catalyses the first committed step in the synthesis of prostanoids, a large family of arachidonic acid metabolites and major target of non-steroidal anti-inflammatory drugs (NSAIDs). COX-2 is the inducible isoform, rapidly expressed in several cell types in response to pro-inflammatory molecules. The interaction between the polypeptide and its corresponding receptor is highly selective. Therefore, it is of interest to inhibit COX2 in the context of inflammation. It is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process. The structure of COX 2 is screened using SP (Standard Precision) method under molecular docking techniques (Computer aided Design) with reference to novel 1-N-substituted-3, 5-diphenyl-2-pyrazoline derivatives. Based on their score and energy few ligands are selected to Induced Fit Docking (IFD) studies and compared with the existing drug molecules. The result showed that the docked ligands maintain favorable interactions with the active site residues of COX-2. All docking studies were performed using the molecular modeling software GLIDE of Schrodinger package.

H2O2 Stimulates Cystic Fibrosis Transmembrane Conductance Regulator through an Autocrine Prostaglandin Pathway, Using Multidrug-Resistant Protein–4

Cystic fibrosis transmembrane conductance regulator (CFTR) activity is essential for the maintenance of airway surface liquid depth, and therefore mucociliary clearance. Reactive oxygen species, increased during inflammatory airway diseases, alter CFTR activity. Here, H2O2 levels in the surface liquid of normal human bronchial epithelial cultures differentiated at the air-liquid interface were estimated, and H2O2-mediated changes in CFTR activity were examined. In Ussing chambers, H2O2-induced anion currents were sensitive to the CFTR inhibitors CFTRinh172 and GlyH-101. These currents were absent in cells from patients with cystic fibrosis. Responses to greater than 500 μM H2O2 were transient. Cyclooxygenase inhibitors blocked the H2O2 response, as did EP1 and EP4 receptor antagonists. A multidrug-resistant protein (MRP) inhibitor and short hairpin RNA directed against MRP4 blocked H2O2 responses. EP1 and EP4 agonists mimicked H2O2 in both control and MRP4 knockdown cells. Thus, H2O2 activates the synthesis, export, and binding of prostanoids via EP4 and, interestingly, EP1 receptors in normal, differentiated human airway epithelial cells to activate cyclic adenosine monophosphate pathways that in turn activate CFTR channels in the apical membrane.

Role of prostaglandins in colorectal tumorigenesis: Localization and expression of COX-1, COX-2, microsomal Prostaglandin E Synthase-1 and the EP2 receptor

Background: Prostaglandins, in particular prostaglandin E2 (PGE2), are elevated in adenomas and colorectal cancers (CRC). Experimental and epidemiological studies have demonstrated reduced incidence of adenomas and CRC by inhibitors of prostanoid synthesis (NSAIDs). This study aimed to characterize the expression and localization of key enzymes/receptors for PGE2 synthesis in adenomas and CRC in comparison to normal colon. Methods: Immunoblotting and immunohistochemistry were used for semi-quantitative and qualitative analysis of COX-1, COX-2, mPGES-1 and the EP2 receptor in biopsies from patients undergoing resection of adenomas or surgery for CRC (Dukes' A-C). Normal colon served as control for the corresponding tumor in each of the CRC patients. Results: COX-1 was decreased significantly in all groups of CRC (Dukes' A-C) compared to normal colon. In contrast, COX-2 was increased, but only in the combined group of CRC. Microsomal PGES-1 was increased in CRC (Duke's B), and EP2 was augmented in adenomas and CRC. The localization was predominantly epithelial in normal colon and in adenomas, while in CRC both epithelial- and stromal expression was demonstrated. Conclusions: The results support the PGE2- pathway, with epithelial- stromal interactions, in the evolvement of adenomas and in the progression of CRC. Co-expression of COX-1 and COX-2 is in line with the preventive effects of non-specific NSAIDs on adenoma formation. The decrease of COX-1, in combination with an increase of COX-2, favors the potential use of selective COX-2 inhibitors as an adjunct therapy in CRC.

Medicinal Chemistry of Antimigraine Drugs

Migraine is one of the most frequent neurological disorder with high impact on the quality of life. Primary headaches such as migraine are pathophysiologically complex disorders. The concept of the trigeminovascular system dysfunction in migraine has led to a number of drug discoveries dramatically changing the treatment options. Acute and prophylactic therapy targeting either the trigeminovascular system or central structures involve several groups of drugs with peculiar medicinal chemistry. In the proposed review up to date concept of treatment strategy, medicinal chemistry data of the drugs used will be summarized. The present review gives detailed information on drugs effective in aborting migraine attacks (by inhibiting prostanoid synthesis, are agonists of serotonin 5-HT1B/D receptors, on the recently introduced CGRP-receptor antagonists) and the drugs recommended for prophylactic treatment (selected beta-adrenergic receptor antagonists, Ca-channel inhibitors, antiepileptics, antidepressants). The pharmacokinetics, fate in the body (absorption, distribution, metabolism, excretion) and significant pharmacological effects as well as the recent bioanalytical methods for their determination are presented.

Anesthetic Effects on γ-Aminobutyric Acid A Receptors

Anesthetic Effects on γ-Aminobutyric Acid A Receptors

IL‐1β/HMGB1 Complexes Promote The PGE2 Biosynthesis Pathway in Synovial Fibroblasts

PGE2 is a potent lipid mediator of pain and oedema found elevated in RA. Microsomal prostaglandin E synthase-1 (mPGES-1) is a terminal enzyme of the PGE2 pathway inducible by proinflammatory cytokines. mPGES-1 is markedly upregulated in RA synovial tissue despite antirheumatic treatments, suggesting that multiple inflammatory stimuli contribute to its induction. High-mobility group box chromosomal protein 1 (HMGB1) is known to induce inflammation both by direct interaction with TLR4 and by enhancement of other proinflammatory molecules signalling, through complex formation. The high expression of extracellular HMGB1 within the inflamed synovium, implies its pro-arthritogenic role in RA. We aimed to investigate the effects of IL-1β/HMGB1 complexes on mPGES-1 and other enzymes of the PGE2 pathway in synovial fibroblasts (SFs) from patients with arthritis. Furthermore, we studied the effect of COX-2 inhibition and IL-1RI antagonism on prostanoid and cytokine production by SFs. Stimulation of SFs with HMGB1 in complex with suboptimal amounts of IL-1β significantly increased mPGES-1 and COX-2 expressions as well as PGE2 production, as compared to treatment with HMGB1 or IL-1β alone. Furthermore, NS-398 reduced the production of IL-6 and IL-8, thus indicating that IL-1β/HMGB1 complexes modulate cytokine production in part through prostanoid synthesis. Treatment with IL-1RA completely abolished the induced PGE2 and cytokine production, suggesting an effect mediated through IL-1RI. IL-1β/HMGB1 complexes promote the induction of mPGES-1, COX-2 and PGE2 in SF. The amplification of the PGE2 biosynthesis pathway by HMGB1 might constitute an important pathogenic mechanism perpetuating inflammatory and destructive activities in rheumatoid arthritis.