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A white adipose-tissue-specific intracellular phospholipase, which releases arachidonic acid from position sn-2 of phospholipids, was recently discovered and named AdPLA. When AdPLA was induced by feeding or by insulin treatment, the arachidonic acid released from phospholipids acted as a precursor for the formation of prostaglandin [E.sub.2] ([PGE.sub.2]). Subsequent activation of the prostaglandin receptor EP3 caused decreased levels of cAMP that led to decreased lipolysis and increased adiposity. Ablation of AdPLA in knockout mice resulted in the reverse sequence of events, with a decline in arachidonic acid release and prostaglandin synthesis and an increase in levels of cAMP, leading to increased lipolysis and a decline in adiposity, even though food intake was not affected. The newly discovered AdPLA enzyme in white adipose tissue functions as a regulator of lipolysis by acting as an antilipolytic agent mediated by increased [PGE.sub.2] formation and decreased intracellular cAMP.

Hematopoietic prostaglandin [D.sub.2] synthase (hPGD.sub.2S) metabolizes cyclooxygenase (COX)-derived [PGH.sub.2] to [PGD.sub.2] and 15-deoxy[[DELTA].sup.12-14] [PGJ.sub.2] ([15d-PGJ.sub.2]). Unlike COX, the role of [hPGD.sub.2]S in host defense is ambiguous. [PGD.sub.2] can be either pro- or antiinflammatory depending on disease etiology, whereas the existence of 15d-[PGJ.sub.2] and its relevance to pathophysiology remain controversial. Herein, studies on [hPGD.sub.2]S KO mice reveal that 15d-[PGJ2] is synthesized in a self-resolving peritonitis, detected by using liquid chromatography-tandem MS. Together with [PGD2] working on its DP1 receptor, 15d-[PGJ.sub.2] controls the balance of pro- vs. antiinflammatory cytokines that regulate leukocyte influx and monocyte-derived macrophage efflux from the inflamed peritoneal cavity to draining lymph nodes leading to resolution. Specifically, inflammation in PhPGD.sub.2S] KOs is more severe during the onset phase arising from a substantial cytokine imbalance resulting in enhanced polymorphonuclear leukocyte and monocyte trafficking. Moreover, resolution is impaired, characterized by macrophage and surprisingly lymphocyte accumulation. Data from this work place [hPGD.sub.2]S at the center of controlling the onset and the resolution of acute inflammation where it acts as a crucial checkpoint controller of cytokine/ chemokine synthesis as well as leukocyte influx and efflux. Here, we provide definitive proof that 15d-[PGJ.sub.2] is synthesized during mammalian inflammatory responses, and we highlight DP1 receptor activation as a potential antiinflammatory strategy. antiinflammatory | cyclooxygnease | drug development | eicosanoids | innate immunity

Animal studies suggest that prostaglandins in skeletal muscles stimulate afferents and contribute to the exercise pressor reflex. However, human data regarding a role for prostaglandins in this reflex are varied, in part because of systemic effects of pharmacological agents used to block prostaglandin synthesis. We hypothesized that local blockade of prostaglandin synthesis in exercising muscles could attenuate muscle sympathetic nerve activity (MSNA) responses to fatiguing exercise. Blood pressure (Finapres), heart rate, and MSNA (microneurography) were assessed in 12 young healthy subjects during static handgrip and postexercise muscle ischemia (PEMI) before and after local infusion of 6 mg of ketorolac tromethamine in saline via Bier block (regional intravenous anesthesia). In the second experiment (n = 10), the same amount of saline was infused via the Bier block. Ketorolac Bier block decreased the prostaglandins synthesis to ~33% of the baseline. After ketorolac Bier block, the increases in MSNA from the baseline during the fatiguing handgrip was significantly lower than that before the Bier block (before ketorolac: [DELTA]502 [+ or -] 111; post ketorolac: [DELTA]348 [+ or -] 62%, P = 0.016). Moreover, the increase in total MSNA during PEMI after ketorolac was significantly lower than that before the Bier block (P = 0.014). Saline Bier block had no similar effect. The observations indicate that blockade of prostaglandin synthesis attenuates MSNA responses seen during fatiguing handgrip and suggest that prostaglandins contribute to the exercise pressor reflex. prostaglandins; exercise; nervous system; sympathetic; regional blood flow

Author(s): Trista E. North [1, 2]; Wolfram Goessling [1, 2]; Carl R. Walkley [1, 3]; Claudia Lengerke [1]; Kamden R. Kopani [1, 2]; Allegra M. Lord [1, 2]; Gerhard J. [...]

Infection during the neonatal period commonly induces apnea episodes, and the proinflammatory cytokine IL-1[beta] may serve as a critical mediator between these events. To determine the mechanism by which IL-1[beta] depresses respiration, we examined a prostaglandin [E.sub.2] (PG[E.sub.2])-dependent pathway in newborn mice and human neonates. IL-1[beta] and transient anoxia rapidly induced brainstem-specific microsomal prostaglandin E synthase-1 (mPGES-1) activity in neonatal mice. Furthermore, IL-1[beta] reduced respiratory frequency during hyperoxia and depressed hypoxic gasping and autoresuscitation in mPGES-1 wild-type mice, but not in mPGES-1 knockout mice. In wild-type mice, PG[E.sub.2] induced apnea and irregular breathing patterns in vivo and inhibited brainstem respiratory rhythm generation in vitro. Mice lacking the EP3 receptor (EP3R) for PG[E.sub.2] exhibited fewer apneas and sustained brainstem respiratory activity, demonstrating that PG[E.sub.2] exerts its respiratory effects via EP3R. In human neonates, the infectious marker C-reactive protein was correlated with elevated PG[E.sub.2] in the cerebrospinal fluid, and elevated central PG[E.sub.2] was associated with an increased apnea frequency. We conclude that IL-1[beta] adversely affects breathing and its control by mPGES-1 activation and PG[E.sub.2] binding to brainstem EP3 receptors, resulting in increased apnea frequency and hypoxia-induced mortality.

Genital tract bacterial infections could induce abortion and are some of the most common complications of pregnancy; however, the mechanisms remain unclear. We investigated the role of prostaglandins (PGs) in the mechanism of bacterial lipopolysaccharide (LPS)induced pregnancy loss in a mouse model, and we hypothesized that PGs might play a central role in this action. LPS increased PG production in the uterus and decidua from early pregnant mice and stimulated cyclooxygenase (COX)-II mRNA and protein expression in the decidua but not in the uterus. We also observed that COX inhibitors prevented embryonic resorption (ER). To study the possible interaction between nitric oxide (NO) and PGs, we administered aminoguanidine, an inducible NO synthase inhibitor. NO inhibited basal PGE and PGF2[alpha] production in the decidua but activated their uterine synthesis and COX-II mRNA expression under septic conditions. A NO donor (S-nitroso-N-acetylpenicillamine) produced 100% ER and increased PG levels in the uterus and decidua. LPS-stimulated protein nitration was higher in the uterus than in the decidua. Quercetin, a peroxynitrite scavenger, did not reverse LPS-induced ER. Our results suggest that in a model of septic abortion characterized by increased PG levels, NO might nitrate and thus inhibit COX catalytic activity. ER prevention by COX inhibitors adds a possible clinical application to early pregnancy complications due to infections. embryonic resorption | uteri | clecidua | peroxynitrite | sepsis

Previous studies utilizing an ex vivo porcine model of intestinal ischemic injury demonstrated that prostaglandin (PG)[E.sub.2] stimulates repair of mucosal barrier function via a mechanism involving [Cl.sup.-] secretion and reductions in paracellular permeability. Further experiments revealed that the signaling mechanism for PG[E.sub.2]-induced mucosal recovery was mediated via type-2 [Cl.sup.-] channels (ClC-2). Therefore, the objective of the present study was to directly investigate the role of ClC-2 in mucosal repair by evaluating mucosal recovery in ischemia-injured intestinal mucosa treated with the selective ClC-2 agonist lubiprostone. Ischemia-injured porcine ileal mucosa was mounted in Ussing chambers, and short-circuit current ([I.sub.sc]) and transepithelial electrical resistance (TER) were measured in response to lubiprostone. Application of 0.01-1 [micro]M lubiprostone to ischemia-injured mucosa induced concentration-dependent increases in TER, with 1 [micro]M lubiprostone stimulating a twofold increase in TER ([DELTA]TER = 26 [OMEGA] * [cm.sup.2]; P < 0.01). However, lubiprostone (1 [micro]M) stimulated higher elevations in TER despite lower [I.sub.sc] responses compared with the nonselective secretory agonist PG[E.sub.2] (1 [micro]M). Furthermore, lubiprostone significantly (P < 0.05) reduced mucosal-to-serosal fluxes of [sup.3]H-labeled mannitol to levels comparable to those of normal control tissues and restored occludin localization to tight junctions. Activation of C1C-2 with the selective agonist lubiprostone stimulated elevations in TER and reductions in mannitol flux in ischemia-injured intestine associated with structural changes in tight junctions. Prostones such as lubiprostone may provide a selective and novel pharmacological mechanism of accelerating recovery of acutely injured intestine compared with the nonselective action of prostaglandins such as PG[E.sub.2]. ischemia; type 2 chloride channels; repair

Recent work demonstrated that the febrile response to peripheral immune stimulation with proinflammatory cytokine IL-I[beta] or bacterial wall lipopolysaccharide (LPS) is mediated by induced synthesis of prostaglandin E2 by the terminal enzyme microsomal prostaglandin E synthase-1 (mPGES-1). The present study examined whether a similar mechanism might also mediate the anorexia induced by these inflammatory agents. Transgenic mice with a deletion of the Ptges gene, which encodes mPGES-1, and wild-type controls were injected intraperitoneally with IL-1[beta], LPS, or saline. Mice were free fed, and food intake was continuously monitored with an automated system for 12 h. Body weight was recorded every 24 h for 4 days. The IL-1 [beta] induced anorexia in wild-type but not knock-out mice, and so it was almost completely dependent on mPGES-1. In contrast, LPS induced anorexia of the same magnitude in both phenotypes, and hence it was independent of mPGES-I. However, when the mice were prestarved for 22 h, LPS induced anorexia and concomitant body weight loss in the knock-out animals that was attenuated compared with the wild-type controls. These data suggest that IL-1[beta] and LPS induce anorexia by distinct immune-to-brain signaling pathways and that the anorexia induced by LPS is mediated by a mechanism different from the fever induced by LPS. However, nutritional state and/or motivational factors also seem to influence the pathways for immune signaling to the brain. Furthermore, both IL-1[beta] and LPS caused reduced meal size but not meal frequency, suggesting that both agents exerted an anhedonic effect during these experimental conditions. inflammation; food intake; body weight; cytokine; prostaglandin [E.sub.2]

After intestinal injury, both the number and type of intestinal epithelial cells must be restored. Intestinal stem cells, located at the base of the intestinal crypt, repopulate the depleted crypt [...]

Renal cortical cyclooxygenase-2 (COX-2) is restricted to the macula densa and adjacent cortical thick ascending limbs (MD/cTALH). Renal cortical COX-2 increases in response to diabetes and renal ablation, both of which are characterized by hyperfiltration and reduced NaCl delivery to the MD due to increased proximal NaCl reabsorption. High-protein intake also induces hyperfiltration and decreases NaCl delivery to the MD due to increased NaCl reabsorption proximally. We investigated whether high protein induces cortical COX-2 and whether cortical COX-2 contributes to high protein-induced hyperfiltration and increased intrarenal renin biosynthesis. Cortical COX-2 increased after protein loading but decreased after protein restriction. COX-2 inhibition attenuated high protein-induced hyperfiltration but had no effect on high protein-induced intrarenal renin elevation. Therefore, induction of cortical COX-2 contributed to high protein-induced hyperfiltration but not intrarenal renin elevation. In the kidney cortex, neuronal nitric oxide synthase (nNOS) is also localized to the MD, and interactions between intrarenal nNOS and COX-2 systems have been proposed. Cortical COX-2 elevation seen in salt restriction was blocked by nNOS inhibiton. Cortical nNOS expression also increased after protein loading, and inhibition of nNOS activity completely reversed high protein-induced cortical COX-2 elevation and hyperfiltration. These results indicate that NO is a mediator of high protein-induced cortical COX-2 elevation and suggest that both intrarenal nNOS and COX-2 systems appear to regulate afferent arteriolar tone and subsequent hyperfiltration seen in high-protein intake. prostaglandin synthase [G.sub.2]/[H.sub.2]; glomerular filtration rate; protein diet doi:10.1152/ajprenal.00500.2005

Abstract: In experimental glomerulonephritis, inhibition of renal prostaglandin (PG) synthesis by nonsteroidal-anti-inflammatory drugs (NSAIDs) moderates proteinuria, yet can induce harmful effects on renal blood flow and [Na.sup.+]-[K.sup.+]-water balance thereby implicating [...]

Abstract A study of the structure-activity relations of the inhibitory effect of flavonoids on lipopolysaccharide (LPS)-induced prostaglandin production was carried out via a comparative examination of 39 flavonoids and related [...]

Human lung epithelial (Calu-3) cells were used to investigate the effects of protease-activated receptor (PAR) stimulation on [Cl.sup.-] secretion. Quantitative RT-PCR (QRT-PCR) showed that Calu-3 cells express PAR-1, -2, and -3 receptor mRNAs, with PAR-2 mRNA in greatest abundance. Addition of either thrombin or the PAR-2 agonist peptide SLIGRL to the basolateral solution of monolayers mounted in Ussing chambers produced a rapid increase in short-circuit current ([I.sub.sc]: thrombin, 21 [+ or -] 2 [micro]A; SLIGRL, 83 [+ or -] 22 [micro]A), which returned to baseline within 5 min after stimulation. Pretreatment of monolayers with the cell-permeant [Ca.sup.2+]-chelating agent BAPTA-AM (50 [micro]M) abolished the increase in [I.sub.sc]. produced by SLIGRL. When monolayers were treated with the cyclooxygenase inhibitor indomethacin (10 [micro]M), nearly complete inhibition of both the thrombin- and SLIGRL-stimulated [I.sub.sc] was observed. In addition, basolateral treatment with the PG[E.sub.2] receptor antagonist AH-6809 (25 [micro]M) significantly inhibited the effects of SLIGRL on [I.sub.sc]. QRT-PCR revealed that Calu-3 cells express mRNAs for CFTR, the [Ca.sup.2+]-activated KCNN4 [K.sup.+] channel, and the KCNQ1 [K.sup.+] channel subunit, which, in association with KCNE3, is known to be regulated by cAMP. Stimulation with SLIGRL produced an increase in apical [Cl.sup.-] conductance that was blocked in cells expressing short hairpin RNAs designed to target CFTR. These results support the conclusion that PAR stimulation of [Cl.sup.-] secretion occurs by an indirect mechanism involving the synthesis and release of prostaglandins. In addition, PAR-stimulated [Cl.sup.-] secretion requires activation of CFTR and at least two distinct [K.sup.+] channels located in the basolateral membrane. cystic fibrosis transmembrane conductance regulator; KCNQ1; calcium-activated potassium channels; KCNN4; cAMP

LPS is known to modulate macrophage responses during sepsis, including cytokine release, phagocytosis, and proliferation. Although agents that elevate cAMP reverse LPS-induced macrophage functions, whether LPS itself modulates cAMP and whether LPS-induced decreases in proliferation are modulated via a cAMP-dependent pathway are not known. Murine macrophages (RAW264.7 cells) were treated with LPS in the presence or absence of inhibitors of prostaglandin signaling, protein kinases, CaM, [G.sub.i] proteins, and NF-[kappa]B translocation or transcription/translation. LPS effects on CaMKII phosphorylation and the expression of relevant adenylyl cyclase (AC) isoforms were measured. LPS caused a significant dose (5-10,000 ng/ml)- and time (1-8 h)-dependent increase in forskolin-stimulated AC activity that was abrogated by pretreatment with SN50 (an NF-[Kappa]B inhibitor), actinomycin D, or cycloheximide, indicating that the effect is mediated via NF-[Kappa]B-dependent transcription and new protein synthesis. Furthermore, LPS decreased the phosphorylation state of CaMKII, and pretreatment with a CaM antagonist attenuated the LPS-induced sensitization of AC. LPS, cAMP, or PKA activation each independently decreased macrophage proliferation. However, inhibition of NF-[Kappa]B had no effect on LPS-induced decreased proliferation, indicating that LPS-induced decreased macrophage proliferation can proceed via PKA-independent signaling pathways. Taken together, these findings indicate that LPS induces sensitization of AC activity by augmenting the stimulatory effect of CaM and attenuating the inhibitory effect of CaMKII on isoforms of AC that are CaMK sensitive. cell culture; prostaglandin; phosphodiesterase; nuclear factor-[Kappa]B; calcium/calmodulin-dependent kinase; calmodulin

It is well established that cyclooxygenase-2 (COX-2) and the neuronal form of nitric oxide synthase (nNOS) are coexpressed in macula densa cells and that the expression of both enzymes is stimulated in a number of high-renin states. To further explore the role of nNOS and COX-2 in renin secretion, we. determined plasma renin activity in mice deficient in nNOS or COX-2. Plasma renin activity was significantly reduced in nNOS -/- mice on a mixed genetic background and in COX-2 -/- mice on either BALB/c or C57/BL6 congenic backgrounds. In additional studies, we accumulated evidence to show an inhibitory influence of [PGE.sub.2] on nNOS expression. In a cultured macula densa cell line, [PGE.sub.2] significantly reduced nNOS mRNA expression, as quantified by real-time RT-PCR. In COX-2 -/- mice, nNOS mRNA expression in the kidney, determined by real-time RT-PCR, was upregulated throughout the postnatal periods, ranging from postnatal day (PND) 3 to PND 60. The induction of nNOS protein expression and NOS activity in COX-2 -/- mice was localized to macula densa cells using immunohistochemistry and NADPH-diaphorase staining methods, respectively. Therefore, these findings reveal that the absence of either COX-2 or nNOS is associated with suppressed renin secretion. Furthermore, the inhibitory effect of PG[E.sub.2] on nNOS mRNA expression indicates a novel interaction between NO and prostaglandin-mediated pathways of renin regulation. juxtaglomerular apparatus; cyclooxygenase-2; neuronal nitric oxide synthase; real-time reverse transcriptase-polymerase chain reaction; plasma renin activity

We examined, by using a specific PGE receptor subtype EP4 agonist and antagonist, the involvement of EP4 receptors in duodenal HC[O.sup.-.sub.3] secretion induced by PG[E.sub.2] and mucosal acidification in rats. Mucosal acidification was achieved by exposing a duodenal loop to 10 mM HCl for 10 min, and various EP agonists were given intravenously 10 min before the acidification. Secretion of HC[O.sup.-.sub.3] was dose-dependently stimulated by AE1-329 (EP4 agonist), the maximal response being equivalent to that induced by sulprostone (EP1/EP3 agonist) or PG[E.sub.2]. The stimulatory action of AE1-329 and PG[E.sub.2] but not sulprostone was attenuated by AE3-208, a specific EP4 antagonist. This antagonist also significantly mitigated the acid-induced HCO3 secretion. Coadministration of sulprostone and AE1-329 caused a greater secretory response than either agent alone. IBMX potentiated the stimulatory action of both sulprostone and AE1-329, whereas verapamil mitigated the effect of sulprostone but not AE1-329. Chemical ablation of capsaicin-sensitive afferent neurons did not affect the response to any of the EP agonists used. We conclude that EP4 receptors are involved in the duodenal HCO3 response induced by PG[E.sub.2] or acidification in addition to EP3 receptors. The process by which HC[O.sup.-.sub.3] is secreted through these receptors differs regarding second-messenger coupling. Stimulation through EP4 receptors is mediated by cAMP, whereas that through EP3 receptors is regulated by both cAMP and [Ca.sup.2+]; yet there is cooperation between the actions mediated by these two receptors. The neuronal reflex pathway is not involved in stimulatory actions of these prostanoids. prostaglandin [E.sub.2]; EP receptor subtype; EP4 receptor

Byline: Tulay Yucel-Lindberg (1), Therese Hallstrom (1), Anna Kats (1), Manal Mustafa (1), Thomas Modeer (1) Keywords: prostaglandin E synthase; prostaglandin E.sub.2; IL-1[beta]; TNF[alpha]; COX-2 Abstract: It is well established that prostaglandin E.sub.2 (PGE.sub.2) plays an important role in inflammatory diseases including periodontitis. Previously we have reported that the inflammatory mediators interleukin-1[beta] (IL-1[beta]) and tumor necrosis factor [alpha] (TNF[alpha] ) stimulate PGE.sub.2 synthesis by inducing mRNA expression of cyclooxygenase-2 (COX-2) in human gingival fibroblasts. In present study the involvement of microsomal prostaglandin E synthase-1 (mPGES-1) in relation to PGE.sub.2 production was investigated. The results showed that IL-1[beta] as well as TNF[alpha] induced mPGES-1 mRNA and protein expression accompanied by enhanced PGE.sub.2 production in gingival fibroblasts. The anti-inflammatory steroid dexamethasone (DEX) inhibited mPGES-1 mRNA and protein expression as well as PGE.sub.2 production induced by IL-1[beta] or TNF[alpha]. The COX-2 specific inhibitor, celecoxib, in contrast to the nonspecific COX inhibitor, indomethacin, markedly reduced mPGES-1 expression induced by IL-1[beta]. The results demonstrate that mPGES-1 regulates PGE.sub.2 production in gingival fibroblasts stimulated by inflammatory mediators IL-1[beta] and TNF[alpha]. This novel pathway may be a potential target for treatment strategies of periodontal disease. Author Affiliation: (1) Department of Pediatric Dentistry, Institute of Odontology, Karolinska Institutet, Huddinge, Sweden Article History: Registration Date: 28/09/2004

Background: The mucus layer protects the gastrointestinal mucosa from mechanical, chemical, and microbial challenge. Mucin 2 (MUC-2) is the most prominent mucin secreted by intestinal epithelial cells. There is accumulating [...]

Crystal structure analysis of the complex between phospholipase A(sub)2 and aristolochic acid at 1.7 angstrom resolution reveals the specific binding of aristolochic acid to the enzyme and the attendant conformational changes in the enzyme leading to the inhibitory action of prostaglandins synthesis. Arachidonic acid is an intermediate in the biosynthesis of prostaglandins.

Cyclooxygenase (COX)-1 or -2 and prostaglandin (PG) synthases catalyze the formation of various PGs and thromboxane (TX) [A.sub.2]. We have investigated the expression and activity of COX-1 and -2 during human megakaryocytopoiesis. We analyzed megakaryocytes from bone marrow biopsies and derived from thrombopoietin-treated [CD34.sup.+] hemopoietic progenitor cells in culture. Platelets were obtained from healthy donors and patients with high platelet regeneration because of immune thrombocytopenia or peripheral blood stem cell transplantation. By immunocytochemistry, COX-1 was observed in [CD34.sup.+] cells and in megakaryocytes at each stage of maturation, whereas COX-2 was induced after 6 days of culture, and remained detectable in mature megakaryocytes. [CD34.sup.+] cells synthesized more PG[E.sub.2] than TX[B.sub.2] (214 [+ or -] 50 vs. 30 [+ or -] 10 pg/[10.sup.6] cells), whereas the reverse was true in mature megakaryocytes (TX[B.sub.2] 8,440 [+ or -] 2,500 vs. PG[E.sub.2] 906 [+ or -] 161 pg/[10.sup.6] cells). By immunostaining, COX-2 was observed in

Prostaglandins and leukotrienes are potent eicosanoid lipid mediators derived from phospholipase-released arachidonic acid that are involved in numerous homeostatic biological functions and inflammation. They are generated by cyclooxygenase isozymes and 5-lipoxygenase, respectively, and their biosynthesis and actions are blocked by clinically relevant nonsteroidal anti-inflammatory drugs, the newer generation coxibs (selective inhibitors of cyclooxygenase-2), and leukotriene modifiers. The prime mode of prostaglandin and leukotriene action is through specific G protein-coupled receptors, many of which have been cloned recently, thus enabling specific receptor agonist and antagonist development. Important insights into the mechanisms of inflammatory responses, pain, and fever have been gleaned from our current understanding of eicosanoid biology., A discovery chain culminating in one of the most important classes of lipid mediators, known as eicosanoids (from the Greek eicosa = twenty; for twenty carbon fatty acid derivatives), was [...]

Ring closing alkyne metathesis and alkyne cross metathesis were used to produce novel prostaglandins and analogues.

A short and efficient two-step methodology for the synthesis of racemic and enantiomeric forms of methyl esters of prostaglanding b(sub)1 using 3-(dimethoxyphosphorylmethyl)cyclopent-2-enone is described. An overall yield of 28% of the prostaglanding B(sub)1 methyl ester is demonstrated.

The ability of nitric oxide and its derivatives to activate and inhibit prostaglandin synthase 1 (PGHS-1) activity is presented. The study indicates that the formation of peroxynitrite is a primary intermediary step in PGHS-1 activation. However, the finding that other forms of nitrogen oxides inhibit the activation of PGHS-1 may have implications in the regulation of vascular function and tone in both atherosclerotic and normal arteries.

A study reports on the first practical synthesis of each of four enantiomerically pure isomers of 5-F2t-isoprostane to be able to examine the biological activity of other isoprostanes. These isomers are potential human hormones. The synthetic technique developed used the chemo-enzymatic resolution of the pseudo-meso diol as a key step. The experiment also established what functions as a general strategy for the assignment of relative configurations in this series.

The antiinflammatory action of aspirin generally has been attributed to direct inhibition of cyclooxygenases (COX-1 and COX-2), but additional mechanisms are likely at work. These include aspirin's inhibition of NF[Kappa]B translocation to the nucleus as well as the capacity of salicylates to uncouple oxidative phosphorylation (i.e., deplete ATP). At clinically relevant doses, salicylates cause cells to release micromolar concentrations of adenosine, which serves as an endogenous ligand for at least four different types of well-characterized receptors. Previously, we have shown that adenosine mediates the antiinflammatory effects of other potent and widely used antiinflammatory agents, methotrexate and sulfasalazine, both in vitro and in vivo. To determine in vivo whether clinically relevant levels of salicylate act via adenosine, via NF[Kappa]B, or via the 'inflammatory' cyclooxygenase COX-2, we studied acute inflammation in the generic murine air-pouch model by using wild-type mice and mice rendered deficient in either COX-2 or p105, the precursor of p50, one of the components of the multimeric transcription factor NF[Kappa]B. Here, we show that the antiinflammatory effects of aspirin and sodium salicylate, but not glucocorticoids, are largely mediated by the antiinflammatory autacoid adenosine independently of inhibition of prostaglandin synthesis by COX-1 or COX-2 or of the presence of p105. Indeed, both inflammation and the antiinflammatory effects of aspirin and sodium salicylate were independent of the levels of prostaglandins at the inflammatory site. These experiments also provide in vivo confirmation that the antiinflammatory effects of glucocorticoids depend, in part, on the p105 component of NF[Kappa]B.

Byline: K. Noguchi (1), M. Shitashige (2), H. Watanabe (1), S. Murota (2), I. Ishikawa (1) Abstract: The purpose of the present study was to investigate the involvement of cyclooxygease-1 (COX-1) and cyclooxygenase-2 (COX-2) in prostaglandin (PG) production by human periodontal ligament (PDL) fibroblasts stimulated with a proinflammatory cytokine, inerleukin-1[beta] (IL-1[beta]), and to examine the effect of interleukin-4 (IL-4), a Th2 cytokine, and interferon-I3 (IFN-I3), a Th1 cytokine, on PG production by the cells. IL-1[beta]-stimulated PDL fibroblasts produced prostaglandin E.sub.2 (PGE.sub.2) in a time-dependent manner. Indomethacin, a non-selective COX-1/COX-2 inhibitor, and NS-398, a selective COX-2 inhibitor, completely inhibited PGE.sub.2 production by IL-1[beta]-stimulated cells. Northern blot analysis showed that COX-2 mRNA was detected in IL-1[beta]-stimulated PDL cells, although not detected in unstimulated cells, while expression of COX-1 mRNA was in the same extent in both the cells. Dexamethasone inhibited COX-2 mRNA expression, COX activity and PGE.sub.2 production in IL-1[beta]-stimulated cells. IL-4 and IFN-I3 suppressed PGE.sub.2 production by IL-1[beta]-stimulated PDL fibroblasts, but COX activity enhanced by IL-1[beta] treatment was significantly inhibited by IL-4, not by IFN-I3. Northern blot analysis showed that IL-4 depressed COX-2 mRNA expression with no effect on COX-1 mRNA expression. On the other hand, IFN-I3 had no effect on expression of COX-1 and -2 mRNA. These data suggest that COX-2 is primarily responsible for PGE.sub.2 production by IL-1[beta]-stimulated human PDL fibroblasts and that IL-4 inhibited PGE.sub.2 production by IL-1[beta]-stimulated PDL fibroblasts through down-regulation of COX-2 expression, while IFN-I3 suppressed the PGE.sub.2 production with no effect on COX-2 expression. Author Affiliation: (1) Department of Periodontology, Graduate School, Faculty of Dentistry, Tokyo Medical and Dental University, 1--5--45, Yushima, Bunkyo-ku, Tokyo, 113--8549, Japan (2) Department of Physiological Chemistry, Graduate School, Faculty of Dentistry, Tokyo Medical and Dental University, 1--5--45, Yushima, Bunkyo-ku, Tokyo, 113--8549, Japan Article History: Registration Date: 14/10/2004

A study was conducted to determine if indomethacin predisposes human gastric cells to injury through inhibition of prostaglandin synthesis, as well as the role of intracellular calcium in the process. Indomethacin was associated with elevated intracellular Ca concentrations and in increased cellular permeability. The observed effects of indomethacin were dependent on concentration and not on the ability to inhibit prostaglandin synthesis. Results showed that indomethacin pretreatment predisposes human gastric cells to injury by agents associated with intracellular Ca accumulation.

A study was conducted to explain the role of cytokines in human colonic fibroblasts in prostaglandin H synthase-2 messenger ribonucleic acid (PGHS-2 mRNA) and protein induction. The findings described the interleukin-1 beta's enhancement of PGHS-2 expression. Moreover, PGHS-2 and PGE synthesis were more prominent in colonic fibroblasts than other neoplastic and non-neoplastic colonic epithelial cells. These findings identify fibroblasts as cell targets for the beneficial use of non-steroidal anti-inflammatory drugs (NSAIDs) in colorectal cancer pain treatment.

Research was conducted to develop a synthesis of 15-deoxy-12-hydroxy-10-(trifluoromethyl)-Delta-7-alkylidenecyclopentenone prostaglandins-1 methyl ester. The objective was to determine an efficient method for the assembly of the C-100 trifluoromethyl prostanoid. Based on the known structure-activity relationships within this series, the compound is expected to exhibit strong antitumor activity. Synthesis involves the preparation of dieneone via an electrocyclic ring-opening reaction and the ionic electrocyclization which yields the carbon skeleton.

The inducible isoform of cyclooxygenase, COX-2 is the one constitutively expressed in the vas deferens of males. The expression of COX-2 in the vas deferens epithelium is not affected by vasectomy but is significantly inhibited by castration. The reaction catalyzed by cyclooxygenase is the limiting step in the synthesis of prostaglandins. The constitutive expression of one of its isoforms in the vas deferens is suggestive of its role in erectile mechanisms.

Byline: Atila Ucar (1), Serpil Dizbay Sak (1), Mehmet Melli (1) Abstract: This study investigated the effects of indomethacin at clinically relevant doses and its chronic usage on intestinal pathology, survival time and intestinal tissue 6-keto prostaglandin F.sub.1[alpha] and leukotriene B.sub.4 level in rats during various periods with different doses. Indomethacin was administered ranging from 0.625 to 5 mg/kg. When used in doses of 0.625 and 1.25 mg/kg, indomethacin caused no apparent intestinal lesions or death during a treatment period of 30 days. On the other hand, all rats died in 7 days when 5 mg/kg of indomethacin was given. Mortality rate reached 53.3% in seven days in the group where 3.75 mg/kg indomethacin was given. The minimal dose of indomethacin, which induced intestinal ulcer and death, was 2.5 mg/kg. The main pathological findings were intestinal ulcers, but no macroscopic and microscopic changes were observed in the stomach. Intestinal tissue 6-keto prostaglandin F.sub.1[alpha] and leukotriene B.sub.4 levels were quantified by enzyme immunoassay after homogenisation and extraction of tissue. In dose-dependent studies, only the dose of indomethacin, 3.75 mg/kg, significantly inhibited intestinal tissue 6-keto prostaglandin F.sub.1[alpha] levels during seven days application period (197.39 +- 24.26 vs 383.66 +- 46.68 ng/g tissue, treatment vs control). 2.5 mg/kg of indomethacin caused no intestinal ulceration on 4th day, however it significantly inhibited intestinal tissue 6-keto prostaglandin F.sub.1[alpha] levels on 4th day in time-dependent studies (190.3 +- 26.62 vs 383.66 +- 46.68 ng/g tissue, treatment vs control). Neither dose-dependent nor time-dependent indomethacin administration changed intestinal tissue leukotriene B.sub.4 level. The results of this study indicated that indomethacin produced enteropathy rather than gastropathy when used chronically in clinically relevant doses in rats. Inhibition of prostaglandin synthesis, which was estimated by quantification of intestinal tissue 6-keto prostaglandin F.sub.1[alpha] level, seemed not to be a prerequisite for its enteropathic effect. Author Affiliation: (1) Department of Pharmacology and Department of Pathology, Medical Faculty of Ankara University, Sihhiye, 06100, Ankara, Turkey Article History: Registration Date: 03/10/2004

Interleukin-1beta induces the biosynthesis of nitric oxide and prostaglandin E2 in mesangial cell cultures from rat kidneys. This induction is enhanced in the presence of insulin and insulin-like growth factor-I (IGF-I) by inducing the translation of inducible nitric oxide and cyclooxygenase. Both IGF-I and insulin also enhances the phosphorylation of the mitogen-activated protein kinase. The implications of these findings on the inflammatory processes taking place in the kidneys are discussed.

Research suggests that lipopolysaccharide fever is prolonged with a microinjection of the cyclooxygenase inhibitor ketorolac. Experiments involving the injection of ketorolac into the anteroventral preoptic region of pathogen-free, male Sprague-Dawley rats are described. The fever is induced by prostaglandin release, which is in turn induced by ketorolac.

Research shows that biochemical cyclic adenosine monophosphate (cAMP) activates bradykinine receptors in rat mesangial cells via the stimulatory pathway of nonapeptide bradykinin on prostaglandin E2 (PGE2) production. Experiments designed to measure the impact of raised cAMP in the presence of PGE2, forskolin and 8-BrcAMO are described.

Intraperitoneal injection of urate increased reduced glutathione (GSH) levels of up to five times the normal in mice. Further, the conversion of arachidonic acid to prostaglandins and 12-hydroxyeicosatetraenoic acid in macrophages was reduced but that for 12-hydroxyheptadecatrienoic acid was stimulated. Administration of a GSH antagonist partly reversed these effects of urate crystals suggesting that the observed effects of urate are mediated by GSH. The effects of intraperitoneal urate on the expression of the two cyclooxygenase isozymes are discussed.

Astrocytes in the brain form a link with neurons, responding to neuronal activity, and synaptically releasing glutamate. It is shown that coactivation of the AMPA/kainate and metabotropic glutamate receptors (mGluRs) on astrocytes, leads cells to release glutamate via a Ca(super2+)-dependent method mediate by prostaglandins. Glutamate release is prevented by pharmacological inhibition of prostaglandin synthesis.

Research shows that brochoconstrictor peptide bradykinin causes the release of biochemicals cyclooxygenase one, cyclooxygenase two and prostaglandin two in human airway smooth muscle cells. Experiments designed to investigate the effects of bradykinin using B1 receptor antagonist des-Arg (super 9), (Leu (super 8))-bradykinin and B2-receptor agonist [Try(Me)(super 8)]bradykinin using Western blotting techniques on human airway smooth muscle cells are reported.

Prostaglandins (PGs) have been detected in many different plants and certain microorganisms. A few prostaglandin-like compounds have also been shown to occur in plants such as flax, Chromolaena morii, and aquatic sedge; and direct precursors (arachidonic acid, di-homo-[Gamma]-linolenic acid and eicosapentaenoic acid) have been detected in a variety of plants and microorganisms, including certain red algae, brown algae, green algae, and saltwater diatoms. Furthermore, arachidonic acid has been found in mosses and a liverwort. It has also been reported that arachidonic acid occurs in certain angiosperms, namely, poplar (Populus balsamifera), wheat germ oil, Aloe vera, and Allium sativum (garlic). In our studies on the possible physiological effects of prostaglandins we found that a PG possibly has an effect on the flowering of the short-day plant Pharbitis nil. It has hastened flower formation by 28 days as compared with controls under inductive conditions (short days), and certain inhibitors of PG-biosynthesis inhibited flowering to a greater or lesser extent. In other physiological studies of prostaglandins, it was found that they have an effect on such aspects as [GA.sub.3]-controlled responses in barley endosperm, inhibition of crown gall tumor formation on potato discs, and certain electron-flow reactions in isolated chloroplasts. In corn leaf segments it has an effect on photosynthesis, nucleic acid metabolism, and protein synthesis. The effect on four plant bioassay systems was negligible. It has also been reported that PGs play a role in the regulation of cell membrane permeability., II. Introduction Prostaglandins were discovered in plants about 20 years ago, but their presence in plants is not widely known; this review is an attempt to remedy that. Two mini-reviews [...]

A study followed the formation of compound I and compound II in prostaglandin H2 synthase I and II using stopped-flow spectrometry, with arachidonic acid and ethyl hydroperoxide as substrates. The formation of compound I and II during reactions catalyzed by PGH2 synthase I and II were correlated with arachidonic acid-dependent oxygen consumption monitored by computerized Clark-style oxygen electrodes. Experimental methods and findings are presented.

Peroxynitrite activates the cyclooxygenase activities of constitutive and inducible prostaglandin endoperoxide synthases by serving as a substrate for the enzymes' peroxidase activities. Activation of purified enzyme is induced by direct addition of peroxynitrite or by in situ generation of peroxynitrite from NO coupling to superoxide anion. Cu,Zn-superoxide dismutase completely inhibits cyclooxygenase activation in systems where peroxynitrite is generated in situ from superoxide. In the murine macrophage cell line RAW264.7, the lipophilic superoxide dismutase-mimetic agents, Cu(II) [(3,5-diisopropylsalicylic acid).sub.2], and Mn(III) tetrakis(1-methyl-4-pyridyl)porphyrin dose-dependently decrease the synthesis of prostaglandins without affecting the levels of NO synthase or prostaglandin endoperoxide synthase or by inhibiting the release of arachidonic acid. These findings support the hypothesis that peroxynitrite is an important modulator of cyclooxygenase activity in inflammatory cells and establish that superoxide anion serves as a biochemical link between NO and prostaglandin biosynthesis.

The synthesis of phenylglycine was utilized to design new chiral nonracemic lithium amide bases. The nonenzymatic enantioselective deprotonation of cylcohexene oxide to (S)-2-cylcohexene-1-ol by utilizing (S)-proline-based bases produced a maximum of 82% ee. The chiral base (S)-2-cyclohexene-1-ol also produced 77% ee when cyclcohexene oxide was converted to (R)-2-cyclohexene-1-ol (R)-2-cyclohexene-1-ol. The transition state model indicated the presence of larger N-substituent compared to the methyl group.

Trypsin resistance induction reflects the relationship of reversible and irreversible inhibitors with apoprotein. Nonsteroidal antiinflamatory agents and isozyme-specific prostaglandin endoperoxide synthase PGHS-1 and PGHS-2 inhibitors rapidly induce resistance to trypsin cleavage. In case of competitive inhibitors, this resistance is reversed through prolonged incubation with trypsin. The selective PGHS-2 inhibitors protect against tryptic cleavage of apoPGHS-1, but fail to suppress the protein's cyclooxygenase activity.

A study of primary cultures of normal human bronchial epithelial cell lines isolated from the trachea and central airways revealed two isoforms of prostaglandin G/H synthase (PGHS), an enzyme catalyzing synthesis of prostaglandins. Northern and immunoblot analysis of PGHS mRNA and PGHS proteins, respectively, identified PGHS-2 as the dominant isoform expressed in the lung epithelial cells.

Prostaglandins (PG) play a key role in the function of the central nervous system. In vitro studies on PG production in cultured cerebral microvascular smooth muscle showed that eicosanoids produced by subconfluent cultures in response to exogenous arachidonate and calcium ionophore are two- to threefold greater than those produced by confluent cultures. PG production was significantly reduced during serum deprivation but was restored with the reintroduction of serum to smooth muscle within six hours. These data suggest that PG production in cultured smooth muscle is serum dependent.