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Treating postoperative (PO) pain is a clinical challenge. Inadequate PO pain management can lead to worse outcomes, for example chronic post-surgical pain. Therefore, acquiring new information on the PO pain mechanism would increase the therapeutic options available. In this paper, we evaluated the role of a natural substance, epigallocatechin-3-gallate (EGCG), on pain and neuroinflammation induced by a surgical procedure in an animal model of PO pain. We performed an incision of the hind paw and EGCG was administered for five days. Mechanical allodynia, thermal hyperalgesia, and motor dysfunction were assessed 24 h, and three and five days after surgery. At the same time points, animals were sacrificed, and sera and lumbar spinal cord tissues were harvested for molecular analysis. EGCG administration significantly alleviated hyperalgesia and allodynia, and reduced motor disfunction. From the molecular point of view, EGCG reduced the activation of the WNT pathway, reducing WNT3a, cysteine-rich domain frizzled (FZ)1 and FZ8 expressions, and both cytosolic and nuclear β-catenin expression, and the noncanonical β-catenin–independent signaling pathways, reducing the activation of the NMDA receptor subtype NR2B (pNR2B), pPKC and cAMP response element-binding protein (pCREB) expressions at all time points. Additionally, EGCG reduced spinal astrocytes and microglia activation, cytokines overexpression and nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB) pathway, downregulating inducible nitric oxide synthase (iNOS) activation, cyclooxygenase 2 (COX-2) expression, and prostaglandin E2 (PGE2) levels. Thus, EGCG administration managing the WNT/β-catenin signaling pathways modulates PO pain related neurochemical and inflammatory alterations.

Ouabain is a cardiac glycoside that has been described as a hormone, with interesting effects on epithelial physiology. We have shown previously that ouabain induces gap junctional intercellular communication (GJIC) in wild, sensitive cells (MDCK-S), but not in cells that have become insensitive (MDCK-I) by modifying their Na+-K+-ATPase. We have also demonstrated that prostaglandin E2 (PGE2) is able to induce increased GJIC by a mechanism other than ouabain, that does not depend on Na+-K+-ATPase. In this work we show, by dye transfer assays, that when MDCK-S and MDCK-I are randomly mixed, to form monolayers, the latter stablish GJIC, because of stimulation by a compound released to the extracellular media, by MDCK-S cells, after treatment with ouabain, as evidenced by the fact that monolayers of only MDCK-I cells, treated with a conditioned medium (CM) that is obtained after incubation of MDCK-S monolayers with ouabain, significantly increase their GJIC. The further finding that either (1) pre-treatment with COX-2 inhibitors or (2) addition to CM of antagonists of EP2 receptor abolish CM’s ability to induce GJIC in MDCK-I monolayers indicate that PGE2 is the GJIC-inducing compound. Therefore, these results indicate that, in addition to direct stimulation, mediated by Na+-K+-ATPase, ouabain enhances GJIC indirectly through the paracrine production of PGE2.

Osteoarthritis (OA) is a common degenerative disease that results in joint inflammation as well as pain and stiffness. A previous study has reported that Cornus officinalis (CO) extract inhibits oxidant activities and oxidative stress in RAW 264.7 cells. In the present study, we isolated bioactive compound(s) by fractionating the CO extract to elucidate its antiosteoarthritic effects. A single bioactive component, morroniside, was identified as a potential candidate. The CO extract and morroniside exhibited antiosteoarthritic effects by downregulating factors associated with cartilage degradation, including cyclooxygenase-2 (Cox-2), matrix metalloproteinase 3 (Mmp-3), and matrix metalloproteinase 13 (Mmp-13), in interleukin-1 beta (IL-1β)-induced chondrocytes. Furthermore, morroniside prevented prostaglandin E2 (PGE2) and collagenase secretion in IL-1β-induced chondrocytes. In the destabilization of the medial meniscus (DMM)-induced mouse osteoarthritic model, morroniside administration attenuated cartilage destruction by decreasing expression of inflammatory mediators, such as Cox-2, Mmp3, and Mmp13, in the articular cartilage. Transverse microcomputed tomography analysis revealed that morroniside reduced DMM-induced sclerosis in the subchondral bone plate. These findings suggest that morroniside may be a potential protective bioactive compound against OA pathogenesis.

Neuroinflammation is a crucial process to maintain homeostasis in the central nervous system (CNS). However, chronic neuroinflammation is detrimental, and it is described in the pathogenesis of CNS disorders, including Alzheimer's disease (AD) and depression. This process is characterized by the activation of immune cells, mainly microglia. The role of the orphan G-protein-coupled receptor 55 (GPR55) in inflammation has been reported in different models. However, its role in neuroinflammation in respect to the arachidonic acid (AA) cascade in activated microglia is still lacking of comprehension. Therefore, we synthesized a novel GPR55 antagonist (KIT 10, 0.1–25 µM) and tested its effects on the AA cascade in lipopolysaccharide (LPS, 10 ng / mL)-treated primary rat microglia using Western blot and EIAs. We show here that KIT 10 potently prevented the release of prostaglandin E2 (PGE2), reduced microsomal PGE2 synthase (mPGES-1) and cyclooxygenase-2 (COX-2) synthesis, and inhibited the phosphorylation of Ikappa B-alpha (IκB-α), a crucial upstream step of the inflammation-related nuclear factor-kappaB (NF-κB) signaling pathway. However, no effects were observed on COX-1 and -2 activities and mitogen-activated kinases (MAPK). In summary, the novel GPR55 receptor antagonist KIT 10 reduces neuroinflammatory parameters in microglia by inhibiting the COX-2/PGE2 pathway. Further experiments are necessary to better elucidate its effects and mechanisms. Nevertheless, the modulation of inflammation by GPR55 might be a new therapeutic option to treat CNS disorders with a neuroinflammatory background such as AD or depression.

The cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) pathway exerts deleterious pleiotropic effects in inflammation-induced gastric carcinogenesis. We aimed to assess the association of genetic variants in prostaglandin-endoperoxide synthase 2 (PTGS2), ATP binding cassette subfamily C member 4 (ABCC4), hydroxyprostaglandin dehydrogenase 15-(NAD) (HPGD), and solute carrier organic anion transporter family member 2A1 (SLCO2A1) PGE2 pathway-related genes with gastric cancer (GC) risk in a European Caucasian population. A hospital-based case-control study gathering 260 GC cases and 476 cancer-free controls was implemented. Using a tagSNP approach, 51 single nucleotide polymorphisms (SNPs) were genotyped through MassARRAY&reg, iPLEX Gold Technology or allelic discrimination by real-time polymerase chain reaction (PCR). Homozygous carriers of the minor allele for both rs689466 and rs10935090 SNPs were associated with a 2.98 and 4.30-fold increased risk for GC, respectively (95% confidence interval (CI): 1.14&ndash, 7.74, p = 0.027, 95% CI: 1.22&ndash, 15.16, p = 0.026), with the latter also being associated with an anticipated diagnosis age. A multifactor dimensionality reduction analysis identified an overall three-factor best interactive model composed of age, rs689466, and rs1678374 that was associated with a 17.6-fold GC increased risk (95% CI: 11.67&ndash, 26.48, p &lt, 0.0001, (cross-validation) CV consistency of 8/10 and accuracy of 0.807). In this preliminary study, several tagSNPs in PGE2 pathway-related genes were identified as risk biomarkers for GC development. This approach may help to identify higher-risk individuals and may contribute to the tailoring screening of GC in intermediate-risk European countries.

The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay detects DNA breakage by labeling the free 3ʹ-hydroxyl termini. Given that genomic DNA breaks arise during early and late stages of apoptosis, TUNEL staining continues to be widely used as a measure of apoptotic cell death. The advantages of the assay include its relative ease of performance and the broad availability of TUNEL assay kits for various applications, such as single-cell analysis of apoptosis in cell cultures and tissue samples. However, as briefly discussed herein, aside from some concerns relating to the specificity of the TUNEL assay itself, it was demonstrated some twenty years ago that the early stages of apoptosis, detected by TUNEL, can be reversed. More recently, compelling evidence from different biological systems has revealed that cells can recover from even late stage apoptosis through a process called anastasis. Specifically, such recovery has been observed in cells exhibiting caspase activation, genomic DNA breakage, phosphatidylserine externalization, and formation of apoptotic bodies. Furthermore, there is solid evidence demonstrating that apoptotic cells can promote neighboring tumor cell repopulation (e.g., through caspase-3-mediated secretion of prostaglandin E2) and confer resistance to anticancer therapy. Accordingly, caution should be exercised in the interpretation of results obtained by the TUNEL and other apoptosis assays (e.g., caspase activation) in terms of apoptotic cell demise.

Secondary hyperparathyroidism (SHP) is a common complication of chronic kidney disease (CKD) that correlates with morbidity and mortality in uremic patients. It is characterized by high serum parathyroid hormone (PTH) levels and impaired bone and mineral metabolism. The main mechanisms underlying SHP are increased PTH biosynthesis and secretion as well as increased glandular mass. The mechanisms leading to parathyroid cell proliferation in SHP are not fully understood. Reduced expressions of the receptors for calcium and vitamin D contribute to the disinhibition of parathyroid cell proliferation. Activation of transforming growth factor-α-epidermal growth factor receptor (TGF-α-EGFR), nuclear factor kappa B (NF-kB), and cyclooxygenase 2- prostaglandin E2 (Cox2-PGE2) signaling all correlate with parathyroid cell proliferation, underlining their roles in the development of SHP. In addition, the mammalian target of rapamycin (mTOR) pathway is activated in parathyroid glands of experimental SHP rats. Inhibition of mTOR by rapamycin prevents and corrects the increased parathyroid cell proliferation of SHP. Mice with parathyroid-specific deletion of all miRNAs have a muted increase in serum PTH and fail to increase parathyroid cell proliferation when challenged by CKD, suggesting that miRNA is also necessary for the development of SHP. This review summarizes the current knowledge on the mechanisms of parathyroid cell proliferation in SHP.

Particulate matter (PM), a major air pollutant, is a complex mixture of solid and liquid particles of various sizes. PM has been demonstrated to cause intracellular inflammation in human keratinocytes, and is associated with various skin disorders, including atopic dermatitis, eczema, and skin aging. Resveratrol is a natural polyphenol with strong antioxidant properties, and its beneficial effects against skin changes due to PM remain elusive. Therefore, in the present study, we investigated the effect of resveratrol on PM-induced skin inflammation and attempted to deduce the molecular mechanisms underlying resveratrol&rsquo, s effects. We found that resveratrol inhibited PM-induced aryl hydrocarbon receptor activation and reactive oxygen species formation in keratinocytes. It also suppressed the subsequent cellular inflammatory response by inhibiting mitogen-activated protein kinase activation. Consequentially, resveratrol reduced PM-induced cyclooxygenase-2/prostaglandin E2 and proinflammatory cytokine expression, including that of matrix metalloproteinase (MMP)-1, MMP-9, and interleukin-8, all of which are known to be central mediators of various inflammatory conditions and aging. In conclusion, resveratrol inhibits the PM-induced inflammatory response in human keratinocytes, and we suggest that resveratrol may have potential for preventing air pollution-related skin problems.

Chronic treatment involving opioids exacerbates both the risk and severity of ischemic stroke. We have provided experimental evidence showing the anti-inflammatory and neuroprotective effects of the &mu, opioid receptor antagonist &beta, funaltrexamine for neurodegenerative diseases in rat neuron/glia cultures and a rat model of cerebral Ischemia/Reperfusion (I/R) injury. Independent of in vitro Lipopolysaccharide (LPS)/interferon (IFN-&gamma, )-stimulated neuron/glia cultures and in vivo cerebral I/R injury in Sprague&ndash, Dawley rats, &beta, funaltrexamine downregulated neuroinflammation and ameliorated neuronal degeneration. Alterations in microglia polarization favoring the classical activation state occurred in LPS/IFN-&gamma, stimulated neuron/glia cultures and cerebral I/R-injured cortical brains. &beta, funaltrexamine shifted the polarization of microglia towards the anti-inflammatory phenotype, as evidenced by decreased nitric oxide, tumor necrosis factor-&alpha, interleukin-1&beta, and prostaglandin E2, along with increased CD163 and arginase 1. Mechanistic studies showed that the suppression of microglia pro-inflammatory polarization by &beta, funaltrexamine was accompanied by the reduction of NF-&kappa, B, AP-1, cyclic AMP response element-binding protein, along with signal transducers and activators of transcription transcriptional activities and associated upstream activators. The effects of &beta, funaltrexamine are closely linked with its action on neuroinflammation by switching microglia polarization from pro-inflammatory towards anti-inflammatory phenotypes. These findings provide new insights into the anti-inflammatory and neuroprotective mechanisms of &beta, funaltrexamine in combating neurodegenerative diseases, such as stroke.

BiodentineTM is a material based on hydrated calcium silicate with odontotropic properties. However, from the clinician&rsquo, s perspective, every material used to fill a tooth&mdash, even those showing the optimal biochemical parameters&mdash, is in fact a foreign body introduced to the organism of the host. Therefore, apart from the chemical parameters of such materials, equally important is the so-called biocompatibility of such materials. The aim of the study was to investigate whether BiodentineTM, used in the regeneration of the pulp-dentine complex, may affect the expression of the enzymes cyclooxygenase 1 (COX1) and cyclooxygenase 2 (COX2) in THP-1 monocytes/macrophages and the amount of prostanoids synthesized by these enzymes-precursors of biologically active prostanoids such as prostaglandin E2 (PGE2) and thromboxane (TXB2) which are mediators of inflammation. An original aspect of this research is the use of the THP-1 monocyte/macrophage cell model and the use of biomaterial in direct contact with cells. In this way we tried to reflect the clinical conditions of regenerative pulp and periodontal tissue treatment using BiodentineTM. The results of our study showed a lack of macrophage activation (measured by flow cytometry) and a lack of stimulation of the expression of the studied cyclooxygenase enzymes (measured by Western blotting and fluorescent microscopy), as well as a lack of increase in the concentration (measured by ELISA method) of their inflammatory mediators (PGE2 and TXB2) in vitro incubated with BiodentineTM.

The aim of this study was to assess the influence of lead (Pb) at low concentrations (imitating Pb levels in human blood in chronic environmental exposure to this metal) on interleukin 1&beta, (IL-1&beta, ) and interleukin 6 (IL-6) concentrations and the activity and expression of COX-1 and COX-2 in THP-1 macrophages. Macrophages were cultured in vitro in the presence of Pb at concentrations of: 1.25 &mu, g/dL, 2.5 &mu, 5 &mu, 10 &mu, g/dL. The first two concentrations of Pb were selected on the basis of our earlier study, which showed that Pb concentration in whole blood (PbB) of young women living in the northern regions of Poland and in the cord blood of their newborn children was within this range (a dose imitating environmental exposure). Concentrations of 5 &mu, g/dL and 10 &mu, g/dL correspond to the previously permissible PbB concentrations in children or pregnant women, and adults. Our results indicate that even low concentrations of Pb cause an increase in production of inflammatory interleukins (IL-1&beta, and IL-6), increases expression of COX-1 and COX-2, and increases thromboxane B2 and prostaglandin E2 concentration in macrophages. This clearly suggests that the development of inflammation is associated not only with COX-2 but also with COX-1, which, until recently, had only been attributed constitutive expression. It can be concluded that environmental Pb concentrations are able to activate the monocytes/macrophages similarly to the manner observed during inflammation.

Lead (Pb) is a heavy metal with a proven neurotoxic effect. Exposure is particularly dangerous to the developing brain in the pre- and neonatal periods. One postulated mechanism of its neurotoxicity is induction of inflammation. This study analyzed the effect of exposure of rat pups to Pb during periods of brain development on the concentrations of selected cytokines and prostanoids in the forebrain cortex, hippocampus and cerebellum. Methods: Administration of 0.1% lead acetate (PbAc) in drinking water ad libitum, from the first day of gestation to postnatal day 21, resulted in blood Pb in rat pups reaching levels below the threshold considered safe for humans by the Centers for Disease Control and Prevention (10 &micro, g/dL). Enzyme-linked immunosorbent assay (ELISA) method was used to determine the levels of interleukins IL-1&beta, IL-6, transforming growth factor-&beta, (TGF-&beta, ), prostaglandin E2 (PGE2) and thromboxane B2 (TXB2). Western blot and quantitative real-time PCR were used to determine the expression levels of cyclooxygenases COX-1 and COX-2. Finally, Western blot was used to determine the level of nuclear factor kappa B (NF-&kappa, B). Results: In all studied brain structures (forebrain cortex, hippocampus and cerebellum), the administration of Pb caused a significant increase in all studied cytokines and prostanoids (IL-1&beta, IL-6, TGF-&beta, PGE2 and TXB2). The protein and mRNA expression of COX-1 and COX-2 increased in all studied brain structures, as did NF-&kappa, B expression. Conclusions: Chronic pre- and neonatal exposure to Pb induces neuroinflammation in the forebrain cortex, hippocampus and cerebellum of rat pups.

The &beta, blocker carvedilol prevents ultraviolet (UV)-induced skin cancer, but the mechanism is unknown. Since carvedilol possesses antioxidant activity, this study investigated whether carvedilol prevents oxidative photodamage of skin, a precursor event in skin carcinogenesis. The effects of carvedilol, metoprolol (a &beta, blocker without antioxidant property), and 4-hydroxycarbazole (4-OHC, a carvedilol synthesis intermediate and a free radical scavenger) were compared on UV- or H2O2-induced cell death and reactive oxygen species (ROS) production in murine epidermal JB6 P+ cells. Although carvedilol attenuated cell death, metoprolol and 4-OHC failed to show protective effects. As expected, increased cellular ROS induced by H2O2 or UV was abolished by carvedilol and 4-OHC, but not by metoprolol. Consistently, carvedilol attenuated the formation of UV-induced cyclobutane pyrimidine dimers (CPDs) and release of prostaglandin E2 in JB6 P+ cells. Carvedilol&rsquo, s activity was further confirmed in full thickness 3D human reconstituted skin, where carvedilol attenuated UV-mediated epidermal thickening, the number of Ki-67 and p53 positive cells as well as CPD formation. Based on pathway-specific Polymerase Chain Reaction (PCR) Array analysis, carvedilol treatment in many cases normalized UV-induced expression changes in DNA repair genes. Thus, carvedilol&rsquo, s photoprotective activity is not attributed to &beta, blockade or direct ROS-scavenging capacity, but likely via DNA repair regulation.

Mast cells (MCs) recognize antigens (Ag) via IgE-bound high affinity IgE receptors (Fc&epsilon, RI) and trigger type I allergic reactions. Fc&epsilon, RI-mediated MC activation is regulated by various G protein-coupled receptor (GPCR) agonists. We recently reported that ionotropic P2X4 receptor (P2X4R) stimulation enhanced Fc&epsilon, RI-mediated degranulation. Since MCs are involved in Ag-independent hypersensitivity, we investigated whether co-stimulation with ATP and GPCR agonists in the absence of Ag affects MC degranulation. Prostaglandin E2 (PGE2) induced synergistic degranulation when bone marrow-derived MCs (BMMCs) were co-stimulated with ATP, while pharmacological analyses revealed that the effects of PGE2 and ATP were mediated by EP3 and P2X4R, respectively. Consistently, this response was absent in BMMCs prepared from P2X4R-deficient mice. The effects of ATP and PGE2 were reduced by PI3 kinase inhibitors but were insensitive to tyrosine kinase inhibitors which suppressed the enhanced degranulation induced by Ag and ATP. MC-dependent PGE2-triggered vascular hyperpermeability was abrogated in a P2X4R-deficient mouse ear edema model. Collectively, our results suggest that P2X4R signaling enhances EP3R-mediated MC activation via a different mechanism to that involved in enhancing Ag-induced responses. Moreover, the cooperative effects of the common inflammatory mediators ATP and PGE2 on MCs may be involved in Ag-independent hypersensitivity in vivo.

The ginseng berry contains a variety of biologically active compounds and has a higher ginsenoside content than its roots. This study focused on the hepatoprotective activity of ginseng berry extract prepared by enzyme treatment (EGB) compared to the non-enzyme-treated ginseng berry extract (GB) and quality control of EGB. The feeding effect of EGB on alcohol-induced liver damage (AILD) was investigated by measuring the serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) compared with those of EtOH-fed mice. Furthermore, cytokine levels in the culture supernatants of EGB- or GB-treated RAW 264.7 cells were determined by enzyme-linked immunosorbent assay. The developed method was applied to the simultaneous quantification of four major ginsenosides in EGB using UPLC-QTOF/MS. Treatment with EGB at a dose of 0.5 or 1 mg/mouse significantly suppressed the AST and ALT levels in mice with AILD. Enzyme-treated ginseng berry was also found to suppress the production of inflammatory mediators like nitric oxide (NO), tumor-necrosis factor-&alpha, (TNF-&alpha, ), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, showing higher activity than that of GB. The amount of ginsenoside Re, F5, F3, and Rd in the EGB obtained using UPLC-QTOF/MS was 45.9, 3.3, 4.0, and 6.2 mg/g, respectively. These results suggest that EGB has a potential effect on AILD, and its hepatoprotective effect provides beneficial insights into developing new candidates for the prevention and cure of AILD. Also, this study demonstrated the utility of UPLC-QTOF/MS-based major compounds for quality control (QC) of EGB.

In this study, we investigate the immunomodulatory effects of a novel antimicrobial peptide, YD1, isolated from Kimchi, in both in vitro and in vivo models. We establish that YD1 exerts its anti-inflammatory effects via up-regulation of the Nrf2 pathway, resulting in the production of HO-1, which suppresses activation of the NF-κB pathway, including the subsequent proinflammatory cytokines IL-1β, IL-6, and TNF-α. We also found that YD1 robustly suppresses nitric oxide (NO) and prostaglandin E2 (PGE2) production by down-regulating the expression of the upstream genes, iNOS and COX-2, acting as a strong antioxidant. Collectively, YD1 exhibits vigorous anti-inflammatory and antioxidant activity, presenting it as an interesting potential therapeutic agent.

2-Arachidonyl-lysophosphatidylethanolamine, shortly 2-ARA-LPE, is a polyunsaturated lysophosphatidylethanolamine. 2-ARA-LPE has a very long chain arachidonic acid, formed by an ester bond at the sn-2 position. It has been reported that 2-ARA-LPE has anti-inflammatory effects in a zymosan-induced peritonitis model. However, it’s action mechanisms are poorly investigated. Recently, resolution of inflammation is considered to be an active process driven by M2 polarized macrophages. Therefore, we have investigated whether 2-ARA-LPE acts on macrophages for anti-inflammation, whether 2-ARA-LPE modulates macrophage phenotypes to reduce inflammation, and whether 2-ARA-LPE is anti-inflammatory in a carrageenan-induced paw edema model. In mouse peritoneal macrophages, 2-ARA-LPE was found to inhibit lipopolysaccharide (LPS)-induced M1 macrophage polarization, but not induce M2 polarization. 2-ARA-LPE inhibited the inductions of inducible nitric oxide synthase and cyclooxygenase-2 in mouse peritoneal macrophages at the mRNA and protein levels. Furthermore, products of the two genes, nitric oxide and prostaglandin E2, were also inhibited by 2-ARA-LPE. However, 1-oleoyl-LPE did not show any activity on the macrophage polarization and inflammatory responses. The anti-inflammatory activity of 2-ARA-LPE was also verified in vivo in a carrageenan-induced paw edema model. 2-ARA-LPE inhibits LPS-induced M1 polarization, which contributes to anti-inflammation and suppresses the carrageenan-induced paw edema in vivo.

Prostaglandin E2 (PGE2) is known to increase glioblastoma (GBM) cell proliferation and migration while cyclooxygenase (COX) inhibition decreases proliferation and migration. The present study investigated the effects of COX inhibitors and PGE2 receptor antagonists on GBM cell biology. Cells were grown with inhibitors and dose response, viable cell counting, flow cytometry, cell migration, gene expression, Western blotting, and gelatin zymography studies were performed. The stimulatory effects of PGE2 and the inhibitory effects of ibuprofen (IBP) were confirmed in GBM cells. The EP2 and EP4 receptors were identified as important mediators of the actions of PGE2 in GBM cells. The concomitant inhibition of EP2 and EP4 caused a significant decrease in cell migration which was not reverted by exogenous PGE2. In T98G cells exogenous PGE2 increased latent MMP2 gelatinolytic activity. The inhibition of COX1 or COX2 caused significant alterations in MMP2 expression and gelatinolytic activity in GBM cells. These findings provide further evidence for the importance of PGE2 signalling through the EP2 and the EP4 receptor in the control of GBM cell biology. They also support the hypothesis that a relationship exists between COX1 and MMP2 in GBM cells which merits further investigation as a novel therapeutic target for drug development.

Endometriosis is a common gynecological disease. Here, we aimed to investigate the anti-fibrotic, anti-inflammatory, and anti-oxidative role of the methyl ester of 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO-Me) on endometriosis. An endometriosis rat model was constructed by intraperitoneally injecting recipient rats with an equivalent of tissue from the uterus of a donor animal. Endometriosis was allowed to develop for seven days. CDDO-Me was administered on the 7th day and for the next 7 days. On day 14, rats were sacrificed, and peritoneal fluid and endometriotic implants were collected. CDDO-Me displayed antioxidant activity by activating the Nfr2 pathway and the expression of antioxidant mediators such as NQO-1 and HO-1. Moreover, it reduced lipid peroxidation and increased glutathione (GSH) levels and superoxide dismutase (SOD) activity. CDDO-Me also showed anti-inflammatory activity by decreasing the expression of pro-inflammatory cytokines in peritoneal fluids and NFkB activation. It, in turn, reduced cyclooxygenase-2 (COX-2) expression in the endometriotic loci and prostaglandin E2 (PGE2) levels in the peritoneal fluids, leading to increased apoptosis and reduced angiogenesis. The reduced oxidative stress and pro-inflammatory microenvironment decreased implants diameter, area, and volume. In particular, CDDO-Me administration reduced the histopathological signs of endometriosis and inflammatory cells recruitment into the lesions, as shown by toluidine blue staining and myeloperoxidase (MPO) activity. CDDO-Me strongly suppressed α-SMA and fibronectin expression and collagen deposition, reducing endometriosis-associated fibrosis. In conclusion, CDDO-Me treatment resulted in a coordinated and effective suppression of endometriosis by modulating the Nrf2 and NFkB pathways.

Despite the availability of the current drug arsenal for pain management, there is still a clinical need to identify new, more effective, and safer analgesics. Based on our earlier study, newly synthesized 1,3,4-oxadiazole derivatives of pyrrolo[3,4-d]pyridazinone, especially 10b and 13b, seem to be promising as potential analgesics. The current study was designed to investigate whether novel derivatives attenuate nociceptive response in animals subjected to thermal or chemical noxious stimulus, and to compare this effect to reference drugs. The antinociceptive effect of novel compounds was studied using the tail-flick and formalin test. Pretreatment with novel compounds at all studied doses increased the latency time in the tail-flick test and decreased the licking time during the early phase of the formalin test. New derivatives given at the medium and high doses also reduced the late phase of the formalin test. The achieved results indicate that new derivatives dose-dependently attenuate nociceptive response in both models of pain and exert a lack of gastrotoxicity. Both studied compounds act more efficiently than indomethacin, but not morphine. Compound 13b at the high dose exerts the greatest antinociceptive effect. It may be due to the reduction of nociceptor sensitization via prostaglandin E2 and myeloperoxidase levels decrease.

Microglial hyperactivation and neuroinflammation are known to induce neuronal death, which is one of the main causes of neurodegenerative disorders. We previously found that Aquilariae Lignum extract attenuated both neuronal excitotoxicity and neuroinflammation in vivo and in vitro. For further analysis, we extracted the methylene chloride fraction of Aquilariae Lignum to determine the bioactive compounds. In this study, we investigated the anti-neuroinflammatory effects and underlying mechanisms of the Aquilariae Lignum fraction (ALF) using lipopolysaccharide (LPS)-stimulated BV2 microglial cells. BV2 cells were pretreated with ALF (0.5, 1, and 2.5 &mu, g/mL) before treatment with LPS (1 &mu, g/mL). Pretreatment with ALF significantly attenuated the LPS-induced overproductions of nitric oxide (NO), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and interleukin (IL)-1&beta, These anti-inflammatory effects were supported by ALF-mediated modulation of the nuclear factor-kappa B (NF-&kappa, B) pathway. Furthermore, ALF exerted strong anti-inflammasome effects, as shown by IL-1&beta, specific inhibitory activity, but not activity against tumor necrosis factor (TNF)-&alpha, along with inhibition of caspase-1 activity and NACHT, LRR, and PYD domain-containing protein 3 (NLRP3)-related molecules. These results indicate the potent anti-neuroinflammatory activity of ALF and that its underlying mechanism may involve the regulation of NLRP3 inflammasome-derived neuroinflammation in microglial cells.

Mitochondrial transcription factor A (TFAM) regulates mitochondrial biogenesis, and it is a candidate target for sensitizing tumor during therapy. Previous studies identified that increased TFAM expression conferred tumor cells resistance to ionizing radiation. However, the mechanisms on how TFAM are regulated in irradiated tumor cells remain to be explored. In this research, we demonstrated the contribution of cyclooxygenase-2 (COX-2) to enhancing TFAM expression in irradiated tumor cells. Our results showed TFAM was concomitantly up-regulated with COX-2 in irradiated tumor cells. Inhibition of COX-2 by NS-398 blocked radiation-induced expression of TFAM, and prostaglandin E2 (PGE2) treatment stimulated TFAM expression. We next provided evidence that DRP1-mediated mitochondrial fragmentation was a reason for TFAM up-regulation in irradiated cells, by using small interfering RNA (siRNA) and selective inhibitor-targeted DRP1. Furthermore, we proved that p38-MAPK-connected COX-2, and DRP1-mediated TFAM up-regulation. Enhanced phosphorylation of p38 in irradiated tumor cells promoted DRP1 expression, mitochondrial fragmentation, and TFAM expression. NS-398 treatment inhibited radiation-induced p38 phosphorylation, while PGE2 stimulated the activation of p38. The results put forward a mechanism where COX-2 stimulates TFAM expression via p38-mediated DRP1/mitochondrial fragmentation signaling in irradiated tumor cells, which may be of value in understanding how to sensitize cancer cells during radiotherapy.

Microsomal prostaglandin E synthetase-1 (mPGES-1) is an inducible terminal enzyme for the production of prostaglandin E2 (PGE2). In experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, mPGES-1 is induced in vascular endothelial cells (VECs) around inflammatory foci and facilitates inflammation, demyelination, and paralysis. Therefore, we investigated the role of CD31-positive VECs in mPGES-1-mediated EAE aggravation using immunohistochemical analysis and imaging of wild-type (wt) and mPGES-1-deficient (mPGES-1&minus, /&minus, ) mice. We demonstrated that EAE induction facilitated vascularity in inflammatory lesions in the spinal cord, and this was significantly higher in wt mice than in mPGES-1&minus, mice. In addition, endothelial interleukin-1&beta, (IL-1&beta, ) production was significantly higher in wt mice than in mPGES-1&minus, mice. Moreover, endothelial PGE2 receptors (E-prostanoid (EP) receptors EP1&ndash, 4) were expressed after EAE induction, and IL-1&beta, was induced in EP receptor-positive VECs. Furthermore, IL-1 receptor 1 expression on VECs was increased upon EAE induction. Thus, increased vascularity is one mechanism involved in EAE aggravation induced by mPGES-1. Furthermore, mPGES-1 facilitated the autocrine function of VECs upon EP receptor induction and IL-1&beta, production, modulating mPGES-1 induction in EAE.

In this study, we investigated the effects of minocycline, a putative suppressor of microglial activation, on systemic lipopolysaccharide (LPS)-induced spinal cord inflammation, allodynia, and hyperalgesia in neonatal rats. Intraperitoneal (i.p.) injection of LPS (2 mg/kg) or sterile saline was performed in postnatal day 5 (P5) rat pups and minocycline (45 mg/kg) or vehicle (phosphate buffer saline, PBS) was administered (i.p.) 5 min after LPS injection. The von Frey filament and tail-flick tests were performed to determine mechanical allodynia (a painful sensation caused by innocuous stimuli, e.g., light touch) and thermal hyperalgesia (a condition of altered perception of temperature), respectively, and spinal cord inflammation was examined 24 h after the administration of drugs. Systemic LPS administration resulted in a reduction of tactile threshold in the von Frey filament tests and pain response latency in the tail-flick test of neonatal rats. The levels of microglia and astrocyte activation, pro-inflammatory cytokine interleukin-1&beta, (IL-1&beta, ), cyclooxygenase-2 (COX-2), and prostaglandin E2 (PGE2) in the spinal cord of neonatal rats were increased 24 h after the administration of LPS. Treatment with minocycline significantly attenuated LPS-induced allodynia, hyperalgesia, the increase in spinal cord microglia, and astrocyte activation, and elevated levels of IL-1&beta, COX-2, and PGE2 in neonatal rats. These results suggest that minocycline provides protection against neonatal systemic LPS exposure-induced enhanced pain sensitivity (allodynia and hyperalgesia), and that the protective effects may be associated with its ability to attenuate LPS-induced microglia activation, and the levels of IL-1&beta, COX-2, and PGE2 in the spinal cord of neonatal rats.

The natural product 6-gingerol, a major bioactive component of the rhizome of ginger (Zingiber officinale), is known to have several beneficial effects on health, including anti-inflammatory activity. The present study aimed to investigate the effects of 6-gingerol on osteoclast differentiation associated with inflammation. 6-Gingerol inhibited osteoclast differentiation in co-cultures of osteoblasts and osteoclast precursor cells in response to the pro-inflammatory cytokine, interleukin (IL)-1. However, it did not affect osteoclast precursor differentiation into osteoclasts induced by the receptor activator of nuclear factor-κB ligand (RANKL), a key cytokine causing osteoclast differentiation. 6-Gingerol inhibited IL-1-induced RANKL expression in osteoblasts, and the addition of RANKL to the co-cultures overcame 6-gingerol-mediated inhibition of osteoclast differentiation. It also suppressed IL-1-induced prostaglandin E2 (PGE2) production in osteoblasts, and the addition of exogenous PGE2 reversed 6-gingerol-mediated inhibition of IL-induced RANKL expression in osteoblasts and osteoclast differentiation in the co-cultures. We found that 6-gingerol reduced PGE2 levels by suppressing enzymatic activities of cyclooxygenase and PGE synthase, which cooperatively catalyze the conversion of arachidonic acid to PGE2. Our findings demonstrate that 6-gingerol inhibits IL-1-induced osteoclast differentiation via suppression of RANKL expression in osteoblasts though reduction of PGE2 levels, suggesting its potential use in treating inflammatory bone destruction associated with excessive PGE2 production.

Tussilagone, extracted from Tussilago farfara is an oriental medicine used for asthma and bronchitis. We investigated its mechanism of action, its inhibitory effects on lipopolysaccharide-induced inflammation in macrophages, and its impact on viability in a cecal ligation and puncture (CLP)-induced mouse model of sepsis. Tussilagone suppressed the expression of the inflammatory mediators, nitric oxide and prostaglandin E2, and the inflammatory cytokines, tumor necrosis factor-alpha (TNF-α) and high-mobility group box 1 (HMGB1), in lipopolysaccharide-stimulated RAW 264.7 cells and peritoneal macrophages. Tussilagone also reduced the activation of the mitogen-activated protein kinases and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) involved in the activation of various inflammatory mediators in activated macrophages. Moreover, tussilagone administration (1 mg/kg and 10 mg/kg) produced decreased mortality and lung injury in CLP-activated septic mice. Augmented expression of cyclooxygenase (COX)-2 and TNF-α in pulmonary alveolar macrophages of septic mice were attenuated by tussilagone administration. Tussilagone also suppressed the induction of nitric oxide, prostaglandin E2, TNF-α and HMGB1 in the serum of the septic mice. Overall, tussilagone exhibited protective effects against inflammation and polymicrobial sepsis by suppressing inflammatory mediators possibly via the inhibition of NF-κB activation and the MAP kinase pathway. These results suggest the possible use of tussilagone for developing novel therapeutic modalities for sepsis and other inflammatory diseases.

Sepsis is an overwhelming systemic response to infection that frequently results in tissue damage, organ failure, and even death. Nitric oxide (NO), prostaglandin E2 (PGE2), and cytokine overproduction are thought to be associated with the immunostimulatory cascade in sepsis. In the present study, we analyzed the anti-inflammatory efficacy of the pheophytin-b on both RAW 264.7 murine macrophage and purified human CD14+ monocytes stimulated with lipopolysaccharide (LPS) and elucidated the mechanisms by analyzing the cell signaling pathways known to be activated in sepsis. Pheophytin-b suppressed the overexpression of NO, PGE2, and cytokines in LPS-stimulated macrophages without inducing cytotoxicity. It also reduced NOS2 and COX-2 mRNA and protein levels. The inhibitory effects on NO, PGE2, and cytokine overproduction arose from the suppression of STAT-1 and PI3K/Akt pathways; no changes in NF-κB, MAPK, and AP-1 signaling were detected. Thus, pheophytin-b may represent a potential candidate to beneficially modulate the inflammatory response in sepsis.

The kidney plays a central role in the regulation of the body water balance. The process of targeting the water channel aquaporin-2 (AQP2) on the apical plasma membrane of the collecting duct (CD) principal cells is mainly regulated by the antidiuretic peptide hormone arginine vasopressin (AVP), which is responsible for the maintenance of water homeostasis. Recently, much attention has been focused on the local factors modulating renal water reabsorption by AQP2 in the collecting ducts, especially prostaglandin E2 (PGE2). PGE2 is a lipid mediator involved in a variety of physiological and pathophysiological processes in the kidney. The biological function of PGE2 is mainly mediated by four G-protein-coupled receptors, namely EP1-4, which couple to drive separate intracellular signaling pathways. Increasing evidence demonstrates that PGE2 is essential for renal water transport regulation via multiple mechanisms. Each EP receptor plays a unique role in regulating water reabsorption in renal collecting ducts. This brief review highlights the role of PGE2 in the regulation of water reabsorption and discusses the involvement of each EP receptor subtype in renal collecting duct. A better understanding of the role of PGE2 in renal water transport process may improve disease management strategies for water balance disorders, including nephrogenic diabetes insipidus.

This study was designed to evaluate the effect of cyclooxygenase-1 (COX-1) inhibitor, SC-560, combined with cisplatin or taxol, on angiogenesis in human ovarian cancer xenografts. Mice were treated with intraperitoneal (i.p.) injections of SC-560 6 mg/kg/day, i.p. injections of cisplatin 3 mg/kg every other day and i.p. injections of taxol 20 mg/kg once a week for 21 days. Vascular endothelial growth factor (VEGF) mRNA levels were detected by reverse transcription-polymerase chain reaction (RT-PCR), microvessel density (MVD) was determined by immunohistochemistry, and prostaglandin E2 (PGE2) levels were determined using ELISA. Expression levels of VEGF mRNA and MVD in treatment groups were inhibited significantly when compared with the control group (p &lt, 0.05 for all), and SC-560 combined with cisplatin displayed a greater reduction in the expression of VEGF and MVD than SC-560 or cisplatin alone (p &lt, 0.05). SC-560 combined with taxol showed a greater inhibition on VEGF mRNA expression than SC-560 or taxol alone (p &lt, 0.05). The level of PGE2 in treatment groups was significantly reduced when compared with the control group (p &lt, 0.01 for all). These findings may indicate that cisplatin or taxol supplemented by SC-560 in human ovarian cancer xenografts enhances the inhibition effect of cisplatin or taxol alone on angiogenesis.

The number of colorectal cancer (CRC) patients is increasing worldwide. Accumulating evidence has shown that the tumor microenvironment (TME), including macrophages, neutrophils, and fibroblasts, plays an important role in the development and progression of CRC. Although targeting the TME could be a promising therapeutic approach, the mechanisms by which inflammatory cells promote CRC tumorigenesis are not well understood. When inflammation occurs in tissues, prostaglandin E2 (PGE2) is generated from arachidonic acid by the enzyme cyclooxygenase-2 (COX-2). PGE2 regulates multiple functions in various immune cells by binding to the downstream receptors EP1, EP2, EP3, and EP4, and plays an important role in the development of CRC. The current therapies targeting PGE2 using non-steroidal anti-inflammatory drugs (NSAIDs) or COX-2 inhibitors have failed due to the global prostanoid suppression resulting in the severe adverse effects despite the fact they could prevent tumorigenesis. Therefore, therapies targeting the specific downstream molecules of PGE2 signaling could be a promising approach. This review highlights the role of each EP receptor in the TME of CRC tumorigenesis and their therapeutic potential., This article belongs to the Special Issue Molecular and Translational Research on Colorectal Cancer

Neurons interact closely with astrocytes via glutamate; this neuron-glia circuit may play a pivotal role in synaptic transmission. On the other hand, astrocytes contact vascular endothelial cells with their end-feet. It is becoming obvious that non-neuronal cells play a critical role in regulating the neuronal activity in the brain. We find that kainic acid (KA) administration induces the expression of microsomal prostaglandin E synthase-1 (mPGES-1) in venous endothelial cells and the prostaglandin E2 (PGE2) receptor prostaglandin E receptor (EP)-3 on astrocytes. Endothelial mPGES-1 exacerbates KA-induced neuronal damage in in vivo experiments. In in vitro experiments, mPGES-1 produces PGE2, which enhances astrocytic Ca2+ levels via the EP3 receptor and increases Ca2+-dependent glutamate release, thus aggravating neuronal injury. This novel endothelium-astrocyte-neuron signaling pathway may be crucial for driving neuronal damage after repetitive seizures and could be a new therapeutic target for epilepsy and other brain disorders.

The fresh rhizome of Zingiber zerumbet Smith (Zingiberaceae) is used as a food flavoring and also serves as a folk medicine as an antipyretic and for analgesics in Taiwan. Zerumbone, a monocyclic sesquiterpene was isolated from the rhizome of Z. zerumbet and is the major active compound. In this study, the anti-inflammatory and antinociceptive effects of zerumbone on arthritis were explored using in vitro and in vivo models. Results showed that zerumbone inhibited inducible nitric oxide (NO) synthase (iNOS), cyclooxygenase (COX)-2 expressions, and NO and prostaglandin E2 (PGE2) production, but induced heme oxygenase (HO)-1 expression in a dose-dependent manner in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. When zerumbone was co-treated with an HO-1 inhibitor (tin protoporphyrin (SnPP)), the NO inhibitory effects of zerumbone were recovered. The above results suggest that zerumbone inhibited iNOS and COX-2 through induction of the HO-1 pathway. Moreover, matrix metalloproteinase (MMP)-13 and COX-2 expressions of interleukin (IL)-1β-stimulated primary rat chondrocytes were inhibited by zerumbone. In an in vivo assay, an acetic acid-induced writhing response in mice was significantly reduced by treatment with zerumbone. Furthermore, zerumbone reduced paw edema and the pain response in a mono-iodoacetate (MIA)-induced rat osteoarthritis model. Therefore, we suggest that zerumbone possesses anti-inflammatory and antinociceptive effects which indicate zerumbone could be a potential candidate for osteoarthritis treatment.