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Background: Prostaglandin D2 (PGD2) signaling via prostaglandin D2 receptor 2 (DP2) contributes to atopic and non-atopic asthma. Inhibiting DP2 has shown therapeutic benefit in certain subsets of asthma patients, improving eosinophilic airway inflammation. PGD2 metabolites prolong the inflammatory response in asthmatic patients via DP2 signaling. The role of PGD2 metabolites on eosinophil and ILC2 activity is not fully understood.Methods: Eosinophils and ILC2s were isolated from peripheral blood of atopic asthmatic patients. Eosinophil shape change, ILC2 migration and IL-5/IL-13 cytokine secretion were measured after stimulation with seven PGD2 metabolites in presence or absence of the selective DP2 antagonist fevipiprant.Results: Selected metabolites induced eosinophil shape change with similar nanomolar potencies except for 9α,11β-PGF2. Maximal values in forward scatter of eosinophils were comparable between metabolites. ILC2s migrated dose-dependently in the presence of selected metabolites except for 9α,11β-PGF2 with EC50 values ranging from 17.4 to 91.7 nM. Compared to PGD2, the absolute cell migration was enhanced in the presence of Δ12-PGD2, 15-deoxy-Δ12,14-PGD2, PGJ2, Δ12-PGJ2 and 15-deoxy-Δ12,14-PGJ2. ILC2 cytokine production was dose dependent as well but with an average sixfold reduced potency compared to cell migration (IL-5 range 108.1 to 526.9 nM, IL-13 range: 125.2 to 788.3 nM). Compared to PGD2, the absolute cytokine secretion was reduced in the presence of most metabolites. Fevipiprant dose-dependently inhibited eosinophil shape change, ILC2 migration and ILC2 cytokine secretion with (sub)-nanomolar potencies.Conclusion: Prostaglandin D2 metabolites initiate ILC2 migration and IL-5 and IL-13 cytokine secretion in a DP2 dependent manner. Our data indicate that metabolites may be important for in vivo eosinophil activation and ILC2 migration and to a lesser extent for ILC2 cytokine secretion. [ABSTRACT FROM AUTHOR]

Current pharmacological treatment options for many bladder contractile dysfunctions are not suitable for all patients, thereby bringing interest to the investigation of therapies that target a combination of receptors. This study aimed to compare responses of PGE2 on the urinary bladder urothelium with lamina propria (U&LP, also called the bladder mucosa) or detrusor smooth muscle and attempt to identify the receptor subtypes mediating PGE2 contractile responses in these tissues. In the presence of selective EP1 – 4 receptor antagonists, varying concentrations of PGE2 were applied to isolated strips of porcine U&LP and detrusor that were mounted in organ baths filled with Krebs-bicarbonate solution and gassed with carbogen. The addition of PGE2 (1 and 10 μM) and PGF2α (10 μM) to U&LP preparations caused significant increases in the baseline tension and in the spontaneous phasic contractile frequency. In detrusor preparations, significant increases in the baseline tension were observed in response to PGE2 (1 and 10 μM) and PGFα (10 μM), and spontaneous phasic contractions were initiated in 83% of preparations. None of the selective PGE2 receptor antagonists inhibited the increases in baseline tension in both U&LP and detrusor. However, the antagonism of PGF2α receptor showed significantly inhibited contractile responses in both layers of the bladder. This study presents prostaglandin receptor systems as a potential regulator of urinary bladder contractility. The main contractile effects of PGE2 in both U&LP and detrusor are mediated via the FP receptor with no observed contribution from any of the four EP receptors.

Current pharmacological treatment options for many bladder contractile dysfunctions are not suitable for all patients, thereby bringing interest to the investigation of therapies that target a combination of receptors. This study aimed to compare responses of PGE2 on the urinary bladder urothelium with lamina propria (U&LP, also called the bladder mucosa) or detrusor smooth muscle and attempt to identify the receptor subtypes mediating PGE2 contractile responses in these tissues. In the presence of selective EP1 – 4 receptor antagonists, varying concentrations of PGE2 were applied to isolated strips of porcine U&LP and detrusor that were mounted in organ baths filled with Krebs-bicarbonate solution and gassed with carbogen. The addition of PGE2 (1 and 10 μM) and PGF2α (10 μM) to U&LP preparations caused significant increases in the baseline tension and in the spontaneous phasic contractile frequency. In detrusor preparations, significant increases in the baseline tension were observed in response to PGE2 (1 and 10 μM) and PGFα (10 μM), and spontaneous phasic contractions were initiated in 83% of preparations. None of the selective PGE2 receptor antagonists inhibited the increases in baseline tension in both U&LP and detrusor. However, the antagonism of PGF2α receptor showed significantly inhibited contractile responses in both layers of the bladder. This study presents prostaglandin receptor systems as a potential regulator of urinary bladder contractility. The main contractile effects of PGE2 in both U&LP and detrusor are mediated via the FP receptor with no observed contribution from any of the four EP receptors. [ABSTRACT FROM AUTHOR]

Increased serum IgE level is one of the features of allergic asthma. It is reported that IgE production can be enhanced by E-prostanoid 2 (EP2) receptor of prostaglandin E2 (PGE2); however, whether E-prostanoid 4 (EP4) receptor (encoded by Ptger4) has a unique or redundant role is still unclear. Here, we demonstrated the mice with B cell-specific deletion of the EP4 receptor (Ptger4 fl/fl Mb1 cre+/−) showed their serum levels of IgE were markedly increased. A much more severe airway allergic inflammation was observed in the absence of EP4 signal using the OVA-induced asthma model. Mechanistic studies demonstrated that the transcription levels of AID, GLTε, and PSTε in EP4-deficient B cells were found to be significantly increased, implying an enhanced IgE class switch. In addition, we saw higher levels of phosphorylated STAT6, a vital factor for IgE class switch. Biochemical analyses indicated that inhibitory effect of EP4 signal on IgE depended on the activation of the PI3K-AKT pathway. Further downstream, PPARγ expression was up-regulated. Independent of its activity as a transcription factor, PPARγ here primarily functioned as an E3 ubiquitin-ligase, which bound the phosphorylated STAT6 to initiate its degradation. In support of PPARγ as a key mediator downstream of the EP4 signal, PPARγ agonist induced the down-regulation of phospho-STAT6, whereas its antagonist was able to rescue the EP4-mediated inhibition of STAT6 activation and IgE production. Thus, our findings highlight a role for the PGE2-EP4-AKT-PPARγ-STAT6 signaling in IgE response, highlighting the therapeutic potential of combined application of EP4 and PPARγ agonists in asthma. [ABSTRACT FROM AUTHOR]

Harboring insulin-producing cells, the pancreas has more interstitial insulin than any other organ. In vitro, insulin activates both insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF1R) to stimulate pancreatic cancer cells. Whether intra-pancreatic insulin nourishes pancreatic cancer cells in vivo remains uncertain. In the present studies, we transplanted human pancreatic cancer cells orthotopically in euglycemic athymic mice whose intra-pancreatic insulin was intact or was decreased following pretreatment with streptozotocin (STZ). In the next eight weeks, the tumor carriers were treated with one of the IR/IGF1R antagonists penta-O-galloyl- β -D-glucose (PGG) and epigallocatechin gallate (EGCG) or treated with vehicle. When pancreatic tumors were examined, their fraction occupied with living cells was decreased following STZ pretreatment and/or IR/IGF1R antagonism. Using Western blot, we examined tumor grafts for IR/IGF1R expression and activity. We also determined proteins that were downstream to IR/IGF1R and responsible for signal transduction, glycolysis, angiogenesis, and apoptosis. We demonstrated that STZ-induced decrease in intra-pancreatic insulin reduced IR/IGF1R expression and activity, decreased the proteins that promoted cell survival, and increased the proteins that promoted apoptosis. These suggest that intra-pancreatic insulin supported local cancer cells. When tumor carriers were treated with PGG or EGCG, the results were similar to those seen following STZ pretreatment. Thus, the biggest changes in examined proteins were usually seen when STZ pretreatment and PGG/EGCG treatment concurred. This suggests that intra-pancreatic insulin normally combated pharmacologic effects of PGG and EGCG. In conclusion, intra-pancreatic insulin nourishes pancreatic cancer cells and helps the cells resist IR/IGF1R antagonism. [ABSTRACT FROM AUTHOR]

Preterm birth occurs with 10% of deliveries and yet accounts for more than 85% of perinatal morbidity and mortality. Management of preterm labor prior to delivery includes a multipronged pharmacologic approach targeting utilization of reproductive hormones for continuation of pregnancy, advancement of fetal lung maturity, and the decrease of uterine contractility (tocolysis). This article will review and compare guidelines on pharmacologic management of preterm labor as recommended by the American College of Obstetricians and Gynecologists and the European Association of Perinatal Medicine. The classifications of drugs discussed include exogenous progesterone, corticosteroids, and tocolytics (β-adrenergic agonists, magnesium sulfate, calcium channel blockers, prostaglandin inhibitors, nitrates, and oxytocin receptor blockers). For each of these drug classes, the following information will be presented: mechanism of action, maternal/fetal side effects, and nursing implications. [ABSTRACT FROM AUTHOR]

Background: Adaptive trial designs have the potential to address common challenges in drug development; they decrease timelines and costs of early drug development and efficiently create data that support future trials in target populations. While allowing for flexibility and evolution, adaptive strategies introduce some complexity to the design and implementation of trial protocols. Previously published work by the authors include a retrospective analysis of time savings using adaptive design and a systematic, 3- step methodology for writing early-phase adaptive integrated protocols. Methods: This article builds on the authors' published work demonstrating the practical implementation of the adaptive protocol writing methodology and discussing the challenges and efficiencies. It describes the integration of an early development program of OBE022, a novel, oral, selective prostaglandin F2a receptor antagonist, intended as a treatment for preterm labor, using 2 interdependent, adaptive trial protocols. The program consisted of first-in-human single and multiple ascending dose parts with assessments of food effect, cardiac safety, proof of concept, and interactions of OBE022 with 4 standard of care medicines. Results: The manuscript shows how the trials were tailored to OBE022's pharmacokinetic and pharmacodynamic characteristics and its therapeutic indication. The use of 2 large interdependent, adaptive protocols was facilitated by the United Kingdom's (UK's) regulatory environment and its acceptance of a rules-guided progression through the program. Changes to the planned trial conduct could be made without impacting on timelines, because they used predefined adaptive options within their authorized boundaries, and could therefore be made as nonsubstantial amendments. The program was successful and achieved its objectives. It was efficient and fast: it required a small number of participants (n=83) and completed from start of protocol writing to first draft of the clinical study report in just 11 months. Conclusions: This program included all key elements of early drug development in 2 interlinked protocols: the assessment of single and multiple ascending doses, food effect, cardiac safety and proof of concept. The approach described in this article demonstrates how early-phase programs can be designed to be performed, analyzed and reported time- and cost-efficiently. [ABSTRACT FROM AUTHOR]

AimsTo summarise the metabolic responses to niacin that can lead to flushing and to critically evaluate flushing mitigation research.Methods and resultsThis comprehensive review of the mechanism of action of niacin-induced flushing critically evaluates research regarding flushing mitigating formulations and agents. Niacin induces flushing through dermal Langerhans cells where the activation of G protein-coupled receptor 109A (GPR109A) increases arachidonic acid and prostaglandins, such as prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)), subsequently activating prostaglandin D(2) receptor (DP(1)), prostaglandin E(2) receptor (EP(2)) and prostaglandin E receptor 4 (EP(4)) in capillaries and causing cutaneous vasodilatation. Controlling niacin absorption rates, inhibiting prostaglandin production, or blocking DP(1), EP(2) and EP(4) receptors can inhibit flushing. Niacin extended-release (NER) formulations have reduced flushing incidence, duration and severity relative to crystalline immediate-release niacin with similar lipid efficacy. Non-steroidal anti-inflammatory drugs (NSAIDs), notably aspirin given 30 min before NER at bedtime, further reduce flushing. An antagonist to the DP(1) receptor (laropiprant) combined with an ER niacin formulation can reduce flushing; however, significant residual flushing occurs with clinically-relevant dosages.ConclusionsNiacin is an attractive option for treating dyslipidemic patients, and tolerance to niacin-induced flushing develops rapidly. Healthcare professionals should particularly address flushing during niacin dose titration.

Prostaglandin endoperoxide H synthase (PGHS) is a heme-enzyme responsible for the conversion of arachidonic acid (AA) to prostaglandin H 2 (PGH 2). PGHS have both oxygenase (COX) and peroxidase (POX) activities and is present in two isoforms (PGHS-1 and -2) expressed in different tissues and cell conditions. It has been reported that PGHS activity is inhibited by the nitrated form of AA, nitro-arachidonic acid (NO 2 AA), which in turn could be synthesized by PGHS under nitro-oxidative conditions. Specifically, NO 2 AA inhibits COX in PGHS-1 as well as POX in both PGHS-1 and -2, in a dose and time-dependent manner. NO 2 AA inhibition involves lowering the binding stability and displacing the heme group from the active site. However, the complete mechanism remains to be understood. This review describes the interactions of PGHS with NO 2 AA, focusing on mechanisms of inhibition and nitration. In addition, using a novel approach combining EPR-spin trapping and mass spectrometry, we described possible intermediates formed during PGHS-2 catalysis and inhibition. This literature revision as well as the results presented here strongly suggest a free radical-dependent inhibitory mechanism of PGHS-2 by NO 2 AA. This is of relevance towards understanding the underlying mechanism of inhibition of PGHS by NO 2 AA and its anti-inflammatory potential. Image 1 • Nitroarachidonic (NO 2 AA) acid represents a potent inhibitor of PGHS. • A new method combining EPR and MS suggests a free-radical dependent mechanism of PGHS inhibition by NO 2 AA nitroalkenes. • NO 2 AA could represent a novel-more selective-anti-inflammatory agent. [ABSTRACT FROM AUTHOR]

The canine luteal phase exhibits several peculiarities compared with other species. In early diestrus, the corpus luteum (CL) is, at least in part, independent of gonadotropins, and prostaglandins (PGs) appear to be among its main regulators. This was also observed with the inhibition in vivo of COX2, when also transcriptional capacity, vascularization and immune-related factors were affected. Here, we aimed to further investigate the potential effects of PGs withdrawal on the CL transcriptome by performing deep RNA sequencing (RNA-Seq). Samples from a previous in vivo study were used; bitches were treated for 5, 10, 20, or 30 days after ovulation with firocoxib (Previcox®), a PTGS2/COX2 inhibitor, or a placebo. Analysis of results was performed with SUSHI (framework from FGCZ) and with pathways and functional networks analyzers. Time-dependent effects were also investigated and used for quality control. More highly represented differentially expressed genes (DEGs, P < 0.01, FDR < 0.1) in the early CL (days 5 and 10) referred to proliferation and immune system, while in the mature CL (days 20 and 30) they were related with steroidogenesis. The absence of genes concomitantly affected by the treatment at all time-points suggested stage-dependency in the observed effects. Little effect was observed on days 5 and 10. Day 20 had the highest number of DEGs (n = 1,741), related with increased immune response. On day 30, DEGs found (n = 552) referred to decreased steroidogenesis and vascularization. Our results suggest the presence of strong compensatory effects in the early CL and multidirectional effects toward gonadotropin-dependency of the CL after COX2 inhibition. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of indomethacin on prostaglandin E2, regulation of inflammation and adipogenesis, and success of fat transplantation in mice. Methods: The mice were randomly divided into 4 groups: group A (free fat group), group B (free fat + stromal vascular fragments group (SVF)), group C (free fat + 200 μM indomethacin group), and group D (free fat + 200 μM indomethacin + SVF group), with 21 mice in each group. Expression levels of adipogenic genes CEBP-α, FABP4 and LPL in each group were determined. Changes in PGE2 level in transplanted adipose tissue, and changes in the expression of NF-κB in apoptotic stem cells induced by different pro-inflammatory treatments were assayed. Results: Compared with group B, the expression levels of adipogenic genes CEBP-α, FABP4 and LPL significantly decreased in groups A, C and D, with group A as the lowest (p < 0.05). Compared with the indomethacin treatment group, the level of inhibition of PGE2 in mice adipose tissue in the indomethacin-free group increased significantly (p < 0.01). The expression of NF-κB in the adipose stem cells from the indomethacin-treated group was significantly lower than that in the indomethacin-treated group after pretreatment with IL-17 or INF-γ + TNF-α. Conclusion: Indomethacin regulates adipogenesis by inhibiting the production of COX2 metabolite, PGE2. It also regulates the local microenvironment, inhibits the inflammatory process, and protects various stem cells. Therefore, it may improve the success rate of fat transplantation. [ABSTRACT FROM AUTHOR]

• After ICH, neurons show features of ferroptosis in vitro, in vivo and in human. • Ferroptosis occurs in the acute phase of ICH. • Ferroptosis presents in perihematoma and distant brain areas of hematoma. • Fer-1 exerts neuroprotective effects in long-term, but not in short term. Intracerebral hemorrhage (ICH) is a devastating subtype of stroke because it has few viable therapeutic options to intervene against primary or second brain injury. Recently, evidence has suggested that ferroptosis, a nonapoptotic form of cell death, is involved in ICH. In this study, we examined whether ICH-induced neuron death is partly ferroptotic in humans and assessed its temporal and spatial characteristics in mice. Furthermore, the ferroptosis inhibitor ferrostatin-1 (Fer-1) was used to examine the role of ferroptosis after ICH. Fold changes in ferroptosis-related gene expression, intracellular iron levels, malondialdehyde (MDA) levels, and both protein levels and cellular localization of cyclooxygenase-2 (COX-2) were measured to monitor ferroptosis. Transmission electron microscopy (TEM) was also performed to examine the ultrastructure of cells after ICH. We found that the expression level of prostaglandin-endoperoxide synthase (PTGS2) was increased in both in vitro and in vivo ICH models; by comparison, expression level of RPL8 was increased in human brain tissue. In mice, iron and MDA levels were significantly increased 3 h after ICH; COX-2 levels were increased at 12 h after ICH and peaked at 3 days after ICH; COX-2 colocalized with NeuN (a neuronal biomarker); and TEM showed that shrunken mitochondria were found at 3 h, 3 days, and 7 days after ICH. Moreover, ICH-induced neurological deficits, memory impairment and brain atrophy were reduced by Fer-1 treatment. Our results demonstrated that neuronal ferroptosis occurs during the acute phase of ICH in brain areas distant from the hematoma and that inhibition of ferroptosis by Fer-1 exerted a long-term cerebroprotective effect. [ABSTRACT FROM AUTHOR]

Passive limb movement and limb muscle stretch in humans and animals are common experimental strategies used to investigate activation of the muscle mechanoreflex independent of contraction-induced metabolite production. Cyclooxygenase (COX) metabolites, however, are produced by skeletal muscle stretch in vitro and have been found to impact various models of mechanoreflex activation. Whether COX metabolites influence the decerebrate rat triceps surae muscle stretch mechanoreflex model remains unknown. We examined the effect of rat triceps surae muscle stretch on the interstitial concentration of the COX metabolite prostaglandin E2 (PGE2). Interstitial PGE2 concentration was increased above baseline values by 4 min of both static (38% increase, P = 0.01) and dynamic (56% increase, P <0.01) triceps surae muscle stretch (n = 10). The 4-min protocol was required to collect enough microdialysis fluid for PGE2 detection. The finding that skeletal muscle stretch in vivo was capable of producing COX metabolites prompted the hypothesis that intra-arterial administration of the COX inhibitor indomethacin (1 mg/kg) would reduce the pressor and cardioaccelerator responses evoked during 30 s (the duration most commonly used in the rat mechanoreflex model) of static and dynamic rat triceps surae muscle stretch. We found that indomethacin had no effect (P > 0.05, n = 9) on the pressor or cardioaccelerator response during 30 s of either static or dynamic stretch. We conclude that, despite the possibility of increased COX metabolite concentration, COX metabolites do not activate or sensitize thin-fiber muscle afferents stimulated during 30 s of static or dynamic hindlimb skeletal muscle stretch in healthy rats. [ABSTRACT FROM AUTHOR]

Background: Ketorolac (KTR) is used as an analgesic drug with an efficacy close to that of the opioid family. It is mainly used for the short term treatment of post-operative pain. It can inhibit the prostaglandin synthesis by blocking cyclooxygenase (COX). Methods: In this investigation, the inherent stability and biochemical interaction of Ketorolac (KTR) and its degradation products have been studiedon the basis of quantum mechanical approaches. Density functional theory (DFT) with B3LYP/ 6-31G (d) has been employed to optimize the structures. Thermodynamic properties, frontier molecular orbital features, dipole moment, electrostatic potential, equilibrium geometry, vibrational frequencies and atomic partial charges of these optimized structureswere investigated. Molecular docking has been performed against prostaglandin H2 (PGH2) synthase protein 5F19 to search the binding affinity and mode(s). ADMET prediction has performed to evaluate the absorption, metabolism and carcinogenic properties. Results: The equilibrium geometry calculations support the optimized structures. Thermodynamic results disclosed the thermal stability of all structures. From molecular orbital data, all the degradents are chemically more reactive than parent drug (except K3). However, the substitution of carboxymethyl radicalin K4 improved the physicochemical properties and binding affinity. ADMET calculations predict the improved pharmacokinetic and non-carcinogenic properties of all degradents. Conclusion: Based on physicochemical, molecular docking, and ADMET calculation, this study can be helpful to understand the biochemical activities of Ketorolac and its degradents and to design a potent analgesic drug. [ABSTRACT FROM AUTHOR]

Aims/Hypothesis: GPR44 (DP2, PTGDR2, CRTh2) is the receptor for the pro-inflammatory mediator prostaglandin D2 (PGD2) and it is enriched in human islets. In rodent islets, PGD2 is produced in response to glucose, suggesting that the PGD2-GPR44/DP2 axis may play a role in human islet function during hyperglycemia. Consequently, the aim of this work was to elucidate the insulinotropic role of GPR44 antagonism in vitro in human beta-cells and in type 2 diabetes (T2DM) patients. Methods: We determined the drive on PGD2 secretion by glucose and IL-1beta, as well as, the impact on insulin secretion by pharmacological GPR44/DP2 antagonism (AZD1981) in human islets and beta-cells in vitro. To test if metabolic control would be improved by antagonizing a hyperglycemia-driven increased PGD2 tone, we performed a proof-of-mechanism study in 20 T2DM patients (average 54 years, HbA1c 9.4%, BMI 31.6 kg/m2). The randomized, double-blind, placebo-controlled cross-over study consisted of two three-day treatment periods (AZD1981 or placebo) separated by a three-day wash-out period. Mixed meal tolerance test (MMTT) and intravenous graded glucose infusion (GGI) was performed at start and end of each treatment period. Assessment of AZD1981 pharmacokinetics, glucose, insulin, C-peptide, glucagon, GLP-1, and PGD2 pathway biomarkers were performed. Results: We found (1) that PGD2 is produced in human islet in response to high glucose or IL-1beta, but likely by stellate cells rather than endocrine cells; (2) that PGD2 suppresses both glucose and GLP-1 induced insulin secretion in vitro; and (3) that the GPR44/DP2 antagonist (AZD1981) in human beta-cells normalizes insulin secretion. However, AZD1981 had no impact on neither glucose nor incretin dependent insulin secretion in humans (GGI AUC C-peptide 1-2h and MMTT AUC Glucose 0-4h LS mean ratios vs placebo of 0.94 (80% CI of 0.90–0.98, p = 0.12) and 0.99 (90% CI of 0.94–1.05, p = 0.45), despite reaching the expected antagonist exposure. Conclusion/Interpretation: Pharmacological inhibition of the PGD2-GPR44/DP2 axis has no major impact on the modulation of acute insulin secretion in T2DM patients. Trial registration: ClinicalTrials.gov . [ABSTRACT FROM AUTHOR]

Study Design: In vitro and in vivo assessment of osteogenic effect by prostacyclin agonist (ONO-1301).Objective: The aim of this study was to investigate the effects of ONO-1301 on in vitro osteoblastic differentiation and in vivo bone formation induced by bone morphogenetic protein (BMP).Summary Of Background Data: Among prostaglandins (PGs), PGE2 is the most abundant in bone tissue and its effects on bone formation have been well studied. PGI2 (prostacyclin) is the second most abundant PG in bone tissue and plays important roles in hemodynamics. However, the effects of PGI2 on osteoblast differentiation and bone regeneration have not been elucidated.Methods: The effects of PGI2 agonist (ONO-1301), with and without recombinant human (rh) BMP-2, on osteoblastic differentiation and cell proliferation were investigated in vitro using alkaline phosphatase (ALP) and WST-1 assays. Murine primary osteoblasts and cell lines (ST2, MC3T3-E1, C2C12, and CH310T1/2) were used for the study. The effects of ONO-1301 on rhBMP-2 induced bone formation were investigated in a mouse model of muscle pouch transplantation (ectopic model) and in a rat model of spinal fusion (orthotopic model).Results: ONO-1301 significantly increased ALP activity in the primary osteoblasts and ST2 cells. In addition, cotreatment with ONO-1301 and rhBMP-2 significantly increased ALP activity in the primary osteoblasts, as well as in ST2 and MC3T3-E1 cells. Cell proliferation was not affected by both ONO-1301 and ONO-1301 as well as rhBMP-2. In the ectopic model, ONO-1301 significantly increased the volume of ectopic bone whose formation was induced by BMP. In addition, in the orthotopic model, ONO-1301 significantly increased bone volume and fusion rate.Conclusion: This study has demonstrated that the PG IP agonist ONO-1301 improves in vitro BMP-2 induced osteoblast differentiation and in vivo ectopic and orthotopic bone formation. The results suggest that ONO-1301 has a potential clinical application as an enhancer of BMP-induced bone formation.Level Of Evidence: N/A. [ABSTRACT FROM AUTHOR]

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Objectives were to determine effects of: 1) handling temperament and administration of flunixin meglumine, an inhibitor of prostaglandin F2a (PGF2a) synthesis, given at the time of embryo transfer, on pregnancy rates in beef cattle embryo transfer recipients; 2) handling temperament and flunixin meglumine on peripheral concentrations of progesterone, cortisol, substance-P, prostaglandin F metabolites (PGFM, (13,14-dihydro-15-keto-PGF2a) and isoprostane 8-epi PGF2a; and 3) flunixin meglumine treatment on proportion of non-pregnant recipient cows returning to estrus within an expected interval. Angus cross beef cows (n = 710) at 7 locations were assigned a body condition score (BCS: 1, emaciated; 9, obese) and a temperament score [0, calm, slow chute exit; walk (n = 352), 1, excited, fast chute exit; jump, trot or run (n = 358)] and were synchronized with Select-Synch with a controlled internal drug release (CIDR) protocol. Estrus detection aids were applied at CIDR removal and cows were observed thrice daily for estrus until 72 h. Recipient cows that expressed estrus and had a corpus luteum received a frozen-thawed embryo on Day 7 after estrus. At the time of transfer, recipient cows were randomly allocated to receive 10 mL of flunixin meglumine im, immediately after transfer (n = 365) or served as an untreated control (n = 345). In a subset of cows (n = 80), ovarian ultrasonography was performed on the day of embryo transfer to determine corpus luteum volume and blood samples were collected twice, at the time of embryo transfer and 7 d later. All cows received estrus detection aids again on Day 14 (7 d after embryo transfer) and were observed for estrus twice daily until Day 24. Accounting for treatment (P > 0.1), embryo transfer difficulty score (P < 0.1), temperament by treatment interaction (P < 0.05), recipient cows with calm temperament had a higher pregnancy rate compared to those with an excited temperament [59.4 (209/352) vs 51.7% (185/358)]. The pregnancy rate for excitable cows without flunixin meglumine was lower (46.3% 81/175) compared to excitable cows that did received flunixin meglumine [56.8% (104/183)], and calm cows that did [59.3% (108/182)] or did not [59.4% (104/170)] receive flunixin meglumine. Proportions of non-pregnant recipient cows returning to estrus on Days 18–24 were not different between flunixin meglumine and control groups, 87.6% (134/153) and 84.0% (137/163), respectively (P > 0.1). At the time of embryo transfer and 7 d later, there were moderate to strong correlations among circulating concentrations of progesterone, cortisol, substance-P, PGFM and isoprostane 8-epi PGF2a. Among excitable cows, progesterone concentrations were lower and cortisol, substance-P, PGFM and isoprostane 8-epi PGF2a concentrations were greater for cows in the control group compared to cows that received flunixin meglumine. In conclusion, administration of flunixin meglumine improved pregnancy rates in excitable recipient cows following embryo transfer without affecting the proportion of non-pregnant cows returning to estrus. [ABSTRACT FROM AUTHOR]

The crucial medicinal plant Dalbergia odorifera T. Chen species belongs to genus Dalbergia, with interesting secondary metabolites, consisting of main classes of flavonoid, phenol, and sesquiterpene derivatives, as well as several arylbenzofurans, quinones, and fatty acids. Biological studies were carried out on extracts, fractions, and compounds from this species involved in cytotoxic assays; antibacterial, antioxidative, anti-inflammatory, antithrombotic, antiplatelet, antiosteosarcoma, antiosteoporosis, antiangiogenesis, and prostaglandin biosynthetic enzyme inhibition activities; vasorelaxant activities; alpha-glucosidase inhibitory activities; and many other effects. In terms of the valuable resources for natural new drugs development, D. odorifera species are widely used as medicinal drugs in many countries for treatment of cardiovascular diseases, cancer, diabetes, blood disorders, ischemia, swelling, necrosis, or rheumatic pain. Although natural products from this plant have been increasingly playing an important role in drug discovery programs, there is no supportive evidence to provide a general insight into phytochemical studies on D. odorifera species and biological activities of extracts, fractions, and isolated compounds. To a certain extent, this review deals with an overview of almost naturally occurring compounds from this species, along with extensive coverage of their biological evaluations. [ABSTRACT FROM AUTHOR]

Prostaglandin D (PGD) released by degranulating mast cells is believed to play a key role in orchestrating mechanisms of inflammation in allergies and asthma. The biological effects of PGD are mediated by D-prostanoid (DP1), CRTH2 (DP2), and thromboxane prostanoid (TP) receptors. The CRTH2 receptor is involved in induction of migration and activation of T helper type 2 (Th) lymphocytes, eosinophils, and basophils; up-regulation of adhesion molecules; and promotion of pro-inflammatory Th-type cytokines (interleukin [IL]-4, 5, 13), whereas the DP receptor is associated with relaxation of smooth muscles, vasodilation, inhibition of cell migration, and apoptosis of eosinophils. A number of CRTH2/PGD receptor antagonists have been investigated in asthma and allergic diseases. The CRTH2 antagonist (OC000459) or dual CRTH2 and TP receptor antagonist (ramatroban) were effective in reducing eosinophilia, nasal mucosal swelling, and clinical symptoms of allergic rhinitis, with the latter drug registered for clinical use in this indication. OC000459 and setipiprant reduced the late but not early phase of response in an allergen challenge in atopic asthmatics. In persistent asthma, some molecules induced limited improvement in lung function, quality of life, and asthma symptoms (OC000459, BI671800), but in other trials with AMG 853 and AZ1981 these findings were not confirmed. The clear discrepancy between animal studies and clinical efficacy of CRTH2 antagonism in allergic rhinitis, and lack of efficacy in a general cohort of asthmatics, highlight the issue of patient phenotyping. There is no doubt that the PGD/CATH2/DP1 pathway plays a key role in allergic inflammation and further studies with selective or combined antagonisms in well defined cohorts of patients are needed. [ABSTRACT FROM AUTHOR]

Purpose: Animal studies suggest that the inhibition of nitric oxide synthase (NOS) affects blood flow differently in different skeletal muscles according to their muscle fibre type composition (oxidative vs glycolytic). Quadriceps femoris (QF) muscle consists of four different muscle parts: vastus intermedius (VI), rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) of which VI is located deep within the muscle group and is generally regarded to consist mostly of oxidative muscle fibres.Methods: We studied the effect of NOS inhibition on blood flow in these four different muscles by positron emission tomography in eight young healthy men at rest and during one-leg dynamic exercise, with and without combined blockade with prostaglandins.Results: At rest blood flow in the VI (2.6 ± 1.1 ml/100 g/min) was significantly higher than in VL (1.9 ± 0.6 ml/100 g/min, p = 0.015) and RF (1.7 ± 0.6 ml/100 g/min, p = 0.0015), but comparable to VM (2.4 ± 1.1 ml/100 g/min). NOS inhibition alone or with prostaglandins reduced blood flow by almost 50% (p < 0.001), but decrements were similar in all four muscles (drug × muscle interaction, p = 0.43). During exercise blood flow was also the highest in VI (45.4 ± 5.5 ml/100 g/min) and higher compared to VL (35.0 ± 5.5 ml/100 g/min), RF (38.4 ± 7.4 ml/100 g/min), and VM (36.2 ± 6.8 ml/100 g/min). NOS inhibition alone did not reduce exercise hyperemia (p = 0.51), but combined NOS and prostaglandin inhibition reduced blood flow during exercise (p = 0.002), similarly in all muscles (drug × muscle interaction, p = 0.99).Conclusion: NOS inhibition, with or without prostaglandins inhibition, affects blood flow similarly in different human QF muscles both at rest and during low-to-moderate intensity exercise. [ABSTRACT FROM AUTHOR]

Novel pyrazolo[1,5- a ]pyridine derivatives were designed, synthesized and evaluated as orally active EP 1 antagonists for the treatment of overactive bladder. Matched molecular pair analysis (MMPA) allowed the design of a new series of pyrazolo[1,5- a ]pyridine derivatives 4 – 6 . Structure-activity relationships (SAR) studies of 4 – 6 were performed, leading to identification of the nanomolar-level EP 1 antagonist 4c , which exhibited good pharmacological effect through intraduodenal (id) administration in a 17-phenyltrinor prostaglandin E2-induced bladder contraction model in rats. [ABSTRACT FROM AUTHOR]

Contents The study investigated, for cycling sheep, synchronizing protocols simultaneously to the standard 'P' protocol using progestogens priming with intravaginal devices and gonadotropin. In November 2014, 90 adult Menz ewes were assigned to either the 'P' protocol, ' PGF' treatment where oestrus and ovulation were synchronized using two injections of prostaglandin 11 days apart or a 'Gn RH' treatment where the ewes had their oestrus and ovulation synchronized with Gn RH (day 0)-prostaglandin (day 6)-Gn RH (day 9) sequence. The ewes were naturally mated at the induced oestrus and the following 36 days. Plasma progesterone revealed that 92% of the ewes were ovulating before synchronization and all, except one, ovulated in response to the applied treatments. All 'P' ewes exhibited oestrus during the 96-hr period after the end of the treatments in comparison with only 79.3% and 73.3% for ' PGF' and 'Gn RH' ewes, respectively ( p < .05). Onset and duration of oestrus were affected by the hormonal treatment ( p < .05); 'Gn RH' ewes showed oestrus earliest and had the shortest oestrous duration. Lambing rate from mating at the induced oestrus was lower for 'P' than for ' PGF' ewes (55.6% and 79.3%, respectively; p < .05). The same trait was also lower for 'P' than for ' PGF' and 'Gn RH' ewes (70.4%, 89.7% and 86.7%, respectively; p < .05) following the 36-day mating period. Prostaglandin and Gn RH analogue-based protocols are promising alternatives for both controlled natural mating and fixed insemination of Menz sheep after the rainy season when most animals are spontaneously cycling. [ABSTRACT FROM AUTHOR]

The article reports a study of the effects of a prostaglandin D2 receptor antagonist, fevipiprant, on various pathophysiological contributors to inflammation in asthma, including eosinophil migration and mast cell degranulation.

Context:Medicinal plants encompass a rich source of active compounds that can neutralize snake venoms or toxins.Costus spicatus(Jacq.) Sw. (Costaceae) is used by the Amazonian population to treat inflammation, pain and other pathological manifestations. Objective:To evaluate the influence ofC. spicatusaqueous extract on edema, peritonitis, nociception, coagulation, haemorrhage and indirect haemolytic activity induced byBothrops atroxvenom (BAV). Materials and methods:Dried and pulverized leaves were extracted with distilled water. Envenoming was induced by administration ofB. atroxsnake venom in Swiss Webster mice. The experimental groups consisted of BAV (at the minimum dose to induce measurable biological responses) andC. spicatusextract (CSE, 1.25, 2.5, 5.0, 7.5 and 10 mg/kg/25 μl phosphate-buffered saline) administered individually and in combination (BAVCSE). PBS was used as a control.In vitroassays were also conducted in order to evaluate phospholipase A2 coagulant activities (indirect haemolytic method). Results:CSE significantly reduced the venom-induced edema and nociception at all concentrations tested and inhibited migration of inflammatory cells at the three least concentrations (5.0, 7.5 and 10 mg/kg/25 μl PBS). CSE was not effective in inhibiting coagulant, haemorrhagic and indirect haemolytic activities of the venom. Discussion and conclusion:The data suggest that CSE could exhibit a central mechanism for pain inhibition, and may also inhibit prostaglandin synthesis. These findings corroborate the traditional administration ofC. spicatusdecoction to treat inflammatory disorders, including those caused byB. atroxenvenomation. [ABSTRACT FROM PUBLISHER]

Hypertension is a major risk factor for many cardiovascular diseases and leads to subsequent concomitant pathologies such as left ventricular hypertrophy ( LVH). Translational approaches using large animals get more important as they allow the use of standard clinical procedures in an experimental setting. Therefore, the aim of this study was to establish a minimally invasive ovine hypertension model using chronic angiotensin II ( ANG II) treatment and to characterize its effects on cardiac remodeling after 8 weeks. Sheep were implanted with osmotic minipumps filled with either vehicle control ( n = 7) or ANG II ( n = 9) for 8 weeks. Mean arterial blood pressure in the ANG II-treated group increased from 87.4 ± 5.3 to 111.8 ± 6.9 mmHg ( P = 0.00013). Cardiovascular magnetic resonance imaging showed an increase in left ventricular mass from 112 ± 12.6 g to 131 ± 18.7 g after 7 weeks ( P = 0.0017). This was confirmed by postmortem measurement of left ventricular wall thickness which was higher in ANG II-treated animals compared to the control group (18 ± 4 mm vs. 13 ± 2 mm, respectively, P = 0.002). However, ANG II-treated sheep did not reveal any signs of fibrosis or inflammatory infiltrates as defined by picrosirius red and H&E staining on myocardial full thickness paraffin sections of both atria and ventricles. Measurements of plasma high-sensitivity C-reactive protein and urinary 8-iso-prostaglandin F2 α were inconspicuous in all animals. Furthermore, multielectrode surface mapping of the heart did not show any differences in epicardial conduction velocity and heterogeneity. These data demonstrate that chronic ANG II treatment using osmotic minipumps presents a reliable, minimally invasive approach to establish hypertension and nonfibrotic LVH in sheep. [ABSTRACT FROM AUTHOR]

We present here the development of a novel virtual screening protocol combining Structure-based and Ligand-based drug design approaches for the identification of mouse mPGES-1 inhibitors. We used the existing 3D structural data of the murine enzyme to hypothesize the inhibitors binding mode, which was the starting point for docking simulations, shape screening, and pharmacophore hypothesis screening. The protocol allowed the identification of 16 mouse mPGES-1 inhibitors with low micromolar activity, which, notably, also inhibit the human enzyme in the same concentration range. The inhibitors predicted binding mode is expected to be the base for the rational drug design of new potent dual species inhibitors of human and murine mPGES-1. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To evaluate safety and toxicokinetic profiles associated with daily oral administration of grapiprant, a new analgesic that selectively blocks the prostaglandin E2 EP4 receptor, to cats. ANIMALS: 24 healthy domestic shorthair cats (12 males and 12 females). PROCEDURES: Cats were randomly assigned (3 of each sex/group) to receive a placebo capsule or grapiprant at 3, 9, or 15 mg/kg, administered PO once daily for 28 days, beginning on day 0. Food consumption and behavior were observed daily, body weight was measured weekly, and clinicopathologic tests were performed on blood and urine samples collected on days - 7, 14, and 25. Blood samples for toxicokinetic analyses were collected after treatment on days 0 and 27. Cats were euthanized on day 28, and full necropsies and histologic evaluations were performed. RESULTS: Grapiprant rapidly reached peak serum concentrations and maintained substantial concentrations throughout the 28-day period. By day 27, maximum serum concentrations ranged from 683 ng/mL to 4,950 ng/mL, which were attained by I to 4 hours after administration. Serum half-lives on day 27 ranged from approximately 2 to 14 hours (median, approx 5 to 6 hours). Grapiprant was well tolerated, and no adverse effects were detected at doses ≤ 15 mg/kg. No significant effects of grapiprant were identified on body weight, food consumption, clinicopathologic variables, or gross or histologic necropsy findings. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested the safety of daily oral administration of grapiprant to cats. Additional studies are needed to evaluate the efficacy of grapiprant for treatment of cats with osteoarthritis. [ABSTRACT FROM AUTHOR]

Ionomycin and A23187 are divalent cation ionophores with a marked preference for calcium. Studies using these ionophores have almost exclusively interpreted their results in the light of calcium elevation. It was the aim of this study to investigate the effects of ionomycin in osteoblatic MC3T3-E1 cells that are not attributable to its ionophoric properties. Thus, we have found that in contrast to A23187, ionomycin shows similar effects on prostaglandin E2 formation as bradykinin and endothelin-1, being potentiated by extracellular nickel and inhibited by cholera toxin and pertussis toxin. Our data strongly suggest that inomycin, at least in part, exerts its effects via specific binding to a G-protein coupled receptor, thereby evoking downstream cellular events like arachidonate release with subsequent prostaglandin formation. [ABSTRACT FROM AUTHOR]

Background: Cyclooxygenase-2-derived prostaglandin E2 (PGE2), a bioactive eicosanoid, has been implicated in many biological processes including reproduction, inflammation and tumor growth. We previously showed that PGE2 stimulated lung cancer cell growth and progression through PGE2 receptor EP2/EP4-mediated kinase signaling pathways. However, the role of PGE2 in controlling lung airway epithelial cell phenotype remains unknown. We evaluated the effects of c-Jun and 3-phosphoinositede dependent protein kinase-1 (PDK1) in mediating epithelial cell hyperplasia induced by PGE2.Method: The bronchial epithelial cell lines BEAS-2B and HBEc14-KT were cultured and then treated with PGE2. PDK1 small interfering RNA (siRNA) and a PDK1 inhibitor, an antagonist of the PGE2 receptor subtype EP4 and EP4 siRNA, c-Jun siRNA, and overexpressions of c-Jun and PDK1 have been used to evaluate the effects on cell proliferation.Results: We demonstrated that PGE2 increased normal bronchial epithelial cell proliferation through induction of PDK1, an ankyrin repeat-containing Ser/Thr kinase implicated in the induction of apoptosis and the suppression of tumor growth. PDK1 siRNA and a PDK1 inhibitor blocked the effects of PGE2 on normal cell growth. The PGE2-induced PDK1 expression was blocked by an antagonist of the PGE2 receptor subtype EP4 and by EP4 siRNA. In addition, we showed that induction of PDK1 by PGE2 was associated with induction of the transcription factor, c-Jun protein. Silencing of c-Jun using siRNA and point mutations of c-Jun sites in the PDK1 gene promoter resulted in blockade of PDK1 expression and promoter activity induced by PGE2. In contrast, overexpression of c-Jun induced PDK1 gene promoter activity and expression followed increased cell proliferation.Conclusion: PGE2 increases normal bronchial epithelial cell proliferation through increased PDK1 gene expression that is dependent on EP4 and induction of c-Jun. Therewith, our data suggest a new role of c-Jun and PDK1 in mediating epithelial cell hyperplasia induced by PGE2. [ABSTRACT FROM AUTHOR]

In healthy humans, tests of the hypothesis that lactic acid, PGE2, or ATP plays a role in evoking the exercise pressor reflex proved controversial. The findings in humans resembled ours in decerebrate rats that individual blockade of the receptors to lactic acid, PGE2, and ATP had only small effects on the exercise pressor reflex provided that the muscles were freely perfused. This similarity between humans and rats prompted us to test the hypothesis that in rats with freely perfused muscles combined receptor blockade is required to attenuate the exercise pressor reflex. We first compared the reflex before and after injecting either PPADS (10 mg/kg), a P2X receptor antagonist, APETx2 (100 µg/kg), an activating acid-sensing ion channel 3 (ASIC) channel antagonist, or L161982 (2 µg/kg), an EP4 receptor antagonist, into the arterial supply of the hindlimb of decerebrated rats. We then examined the effects of combined blockade of P2X receptors, ASIC3 channels, and EP4 receptors on the exercise pressor reflex using the same doses, intra-arterial route, and time course of antagonist injections as those used for individual blockade. We found that neither PPADS (n = 5), APETx2 (n = 6), nor L161982 (n = 6) attenuated the reflex. In contrast, combined blockade of these receptors (n = 7) attenuated the peak (227%, P < 0.019) and integrated (↓48%, P < 0.004) pressor components of the reflex. Combined blockade injected intravenously had no effect on the reflex. We conclude that combined blockade of P2X receptors, ASIC3 channels, and EP4 receptors on the endings of thin fiber muscle afferents is required to attenuate the exercise pressor reflex in rats with freely perfused hindlimbs. [ABSTRACT FROM AUTHOR]

Natural quinones, often linked with cellular oxidation processes, exhibit pronounced biological activity. In particular, the structurally unique isothiazolonaphthoquinone aulosirazole, isolated from blue-green alga, possesses selective antitumor cytotoxicity, although its mechanism of action is unknown. The first synthesis of aulosirazole uses a route centered upon a late-stage regioselective Diels-Alder reaction. The structurally related natural product pronqodine A, an inhibitor of prostaglandin release, and analogues thereof, were also prepared for comparison. Biological evaluation of the compounds identified one potential target as the immunoregulatory enzyme indoleamine-2,3-dioxygenase (IDO). The isothiazoloquinones are also efficient substrates for the human quinone reductase NQO1, and undergo intracellular NQO1-dependent redox cycling resulting in the generation of reactive oxygen species, and at lower doses have the potential to alter the ratio of intracellular oxidized to reduced pyridine nucleotides. [ABSTRACT FROM AUTHOR]

The chemoattractant receptor-homologous molecule expressed on T-helper 2 cells (CRTH2) is a G-protein-coupled receptor for prostaglandin D2, a key mediator in inflammatory disorders. In this randomized, double-blind, placebo-controlled study we investigated the single- and multiple-dose tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) up to a dose of 800 mg once a day of ACT-453859, a potent and selective CRTH2 antagonist. ACT-453859 was moderately rapidly absorbed and followed a biphasic elimination pattern, with an elimination half-life between 11 and 20 hours. Steady-state conditions were reached after 1 day, and ACT-453859 did not accumulate. Urinary excretion of unchanged ACT-453859 did not exceed 1.4% of the administered dose. Administration of ACT-453859 resulted in a dose-dependent blockadeof CRTH2 on the surface of eosinophils. The maximum PD effect of ACT-453859 was reached about 2.0 hours after dosing, which corresponded to the highest concentration at which PD were assessed. At steady state, 100 and 800 mg ACT-453859 once a day resulted in blockade of CRTH2 over 24 hours. In this entry-into-humans study, ACT-453859 showed good tolerability at all doses and a PK and PD profile compatible with once-daily dosing. [ABSTRACT FROM AUTHOR]

More than 10% of the world's population is chronically infected with HIV, hepatitis C virus (HCV) or hepatitis B virus (HBV), all of which can cause severe disease and death. These viruses persist in part because continuous antigenic stimulation causes the deterioration of virus-specific cytotoxic T lymphocyte (CTL) function and survival. Additionally, antiviral CTLs autonomously suppress their responses to limit immunopathology by upregulating inhibitory receptors such as programmed cell death 1 (PD-1). Identification and blockade of the pathways that induce CTL dysfunction may facilitate the clearance of chronic viral infections. We found that the prostaglandin E2 (PGE2) receptors EP2 and EP4 were upregulated on virus-specific CTLs during chronic lymphocytic choriomeningitis virus (LCMV) infection and suppressed CTL survival and function. We show that the combined blockade of PGE2 and PD-1 signaling was therapeutic in terms of improving viral control and augmenting the numbers of functional virus-specific CTLs. Thus, PGE2 inhibition is both an independent candidate therapeutic target and a promising adjunct therapy to PD-1 blockade for the treatment of HIV and other chronic viral infections. [ABSTRACT FROM AUTHOR]

Background: Di(2-ethylhexyl) phthalate (DEHP) exposure reduces embryo implantations, increases embryonic loss, and decreases fetal body weights. However, whether it is associated with the alteration of luteal function remains unknown. Thus, our aim in this study was to explore the effect and mechanism of DEHP on luteal function in pregnant mice in vivo. Methods: Mice were administered DEHP by gavage at 125, 250, 500 mg/kg/day from gestational days (GD) 1 to 9 or 13. Levels of serum progesterone and estradiol were measured by radioimmunoassay. The numbers and sizes of corpora lutea were calculated by ovarian histomorphology. Steroidogenic enzymes were assessed by qRT-PCR. CD31 protein was detected by immunocytochemistry, and prostaglandin F2alpha (PGF2alpha) levels were evaluated by enzyme immunoassay. Results: Treatment with DEHP significantly inhibited progesterone secretion in pregnant mice in a dose-dependent manner but did not inhibit estradiol production on GD 9 and 13. Treatment also showed concomitant decreases in transcript levels for key steroidogenic enzymes (CYP11A, 3β-HSD, and StAR) on GD 13. Furthermore, DEHP administration significantly reduced the numbers and sizes of corpora lutea on GD 13. No significant changes in the ratio of ovary weight vs. body weight were observed between the control group and treated animals on GD 9 and 13. In addition, treatment with DEHP significantly inhibited CD31 expression of corpora lutea, whereas plasma PGF2alpha levels in DEHP treatment groups were significantly higher compared with the control groups on GD 9 and 13. Conclusions: The results show DEHP significantly inhibits luteal function of pregnant mice in vivo, with a mechanism that seems to involve the down-regulation of progesterone and steroidogenic enzymes message RNA, the decrease in CD31 expression, and the increase in PGF2alpha secretion. [ABSTRACT FROM AUTHOR]

Previous research has determined that PGF2α detrimentally affects pregnancy via direct effects on early embryonic development. Because early embryonic loss is relatively prevalent in lactating dairy cows, we hypothesized that pregnancy retention (and resulting conception rates) would be improved by administering a PGF2α receptor antagonist (AL-8810) shortly after insemination. Multiparous, lactating Holstein dairy cows were randomly assigned to receive one of four intrauterine treatments: (1) control group–untreated cohort (CON; n = 93); (2) control group–vehicle infusion (CON-V; n = 90); (3) 2000 nM AL-8810 infusion (AL-2000; n = 96); or (4) 10,000 nM AL-8810 infusion (AL-10,000; n = 93). Treatments were administered transcervically 4 days after insemination in the horn ipsilateral to the CL. There was no effect of treatment on conception rate (36.6%, 38.9%, 25.0%, and 35.5% for CON, CON-V, AL-2000, and AL-10,000, respectively) or calving rate (24.7%, 24.4%, 16.7%, and 28.0% for CON, CON-V, AL-2000, and AL-10,000, respectively). There was a significant effect of treatment on return to estrus with CON-V (23.6 ± 0.6) and AL-10,000 (23.3 ± 0.6) groups having a longer interval to next estrus over the CON group (21.5 ± 0.6; P < 0.05). Prior treatment did not affect conception to the subsequent insemination. It is important to note that although the addition of AL-8810 into the uterus on Day 4 after insemination did not increase conception rates in the present experiment, it also did not have a negative impact. Furthermore, the treatment procedure itself did not impair the establishment of pregnancy (CON vs. CON-V, AL-2000, and AL-10,000). These results demonstrate that a therapeutic agent can be administered directly into the uterus on Day 4 after insemination without detrimentally affecting conception rates. [ABSTRACT FROM AUTHOR]

We discovered the prostaglandin transporter (PGT) and cloned the human cDNA and gene. PGT transports extracellular prostaglandins (PGs) into the cytoplasm for enzymatic inactivation. PGT knockout mice have elevated prostaglandin E2 (PGE2) and neonatal patent ductus arteriosus, which reflects PGT's control over PGE2 signaling at EP1/EP4 cell-surface receptors. Interestingly, rescued PGT knockout pups have a nearly normal phenotype, as do human PGT nulls. Given the benign phenotype of PGT genetic nulls, and because PGs are useful medicines, we have approached PGT as a drug target. Triazine library screening yielded a lead compound of inhibitory constant 50% (IC50) 3.7 μM, which we developed into a better inhibitor of IC50 378 nM. Further structural improvements have yielded 26 rationally designed derivatives with IC50 < 100 nM. The therapeutic approach of increasing endogenous PGs by inhibiting PGT offers promise in diseases such as pulmonary hypertension and obesity. [ABSTRACT FROM AUTHOR]

Background While studying a urothelium-derived inhibitory factor in guinea pig urinary bladders we observed considerable release of prostanoids, including PGD 2 -like activity. The present study was carried out to identify the prostanoids and to study their roles in modulating guinea pig urinary bladder motility. Methods Release of PGE 2 and PGD 2 in isolated guinea pig urinary bladder preparations was analyzed by high performance liquid chromatography (HPLC) combined with bioassay on bladder strips. Isolated urothelium-intact (UI) or -denuded (UD) bladder strips were subjected to electrical field stimulation (EFS) and applications of PGE 2 and PGD 2 . Results A resting release of 95 ± 9 (n = 5) ng g tissue − 1 h − 1 PGE 2 -like activity and 210 ± 34 (n = 4) ng g tissue − 1 h − 1 PGD 2 -like activity was found, where PGD 2 -like was subject to marked spontaneous inactivation during isolation. Prostanoids release was decreased by 70–90% by the cyclo-oxygenase inhibitor diclofenac in UI preparations. Urothelium removal decreased prostanoids release by more than 90%. PGE 2 increased basal tone and spontaneous contractions, whereas PGD 2 had little or no effect on these. Exogenous PGE 2 enhanced and PGD 2 inhibited contractile responses to EFS, exogenous acetylcholine- and ATP, whereas PGD 2 caused marked dose-dependent inhibition. PGE 2 and PGD 2 effects were more pronounced in diclofenac-treated UD tissues. Conclusions PGD 2 and PGE 2 are released from guinea pig bladder urothelium and PGD 2 has inhibitory effects on bladder motility, mainly through a postjunctional action on smooth muscle responsiveness. General significance The release and inhibitory effects merit further studies in relation to normal biological function as well as overactive bladder syndrome. [ABSTRACT FROM AUTHOR]

Nonsteroidal anti-inflammatory drugs (NSAIDs) act through inhibiting prostaglandin synthesis, a catalytic activity possessed by two distinct cyclooxygenase (COX-1 and COX-2) isozymes encoded by separate genes. The discovery of COX-2 launched a new era in NSAID pharmacology, resulting in the synthesis, marketing, and widespread use of COX-2 selective inhibitors. Extensive structural studies of the biology of prostaglandin synthesis and inhibition have explained some of the differences between COX-1 and COX-2 functionality, but others are still unexplained. Notably these include molecular differences that cause COX-1 inhibitors to produce a slight decrease, and COX-2 inhibitors to induce a significant increase, in heart attacks and strokes. These differences were unexpected because of the 60% overall COX-1 and COX-2 sequence similarity and the 1–2 conservation of catalytic sites. Hydropathic analysis shows important bicyclic differences between COX-1 and COX-2 on a large scale outside the catalytic pocket. These differences involve much stronger amphiphilic interactions in COX-2 than in COX-1, and may explain the selective antiplatelet effectiveness of COX-2. Success of the non-Euclidean structural analysis is the result of using the new Brazilian hydropathicity scale based on self-organized criticality (SOC) of universal protein modules. [ABSTRACT FROM AUTHOR]