Prostaglandin Pathway Research Articles

Association study of genes related to bone formation and resorption and the extent of radiographic change in ankylosing spondylitis

ObjectiveTo identify genetic associations with severity of radiographic damage in ankylosing spondylitis (AS).MethodWe studied 1537 AS cases of European descent; all fulfilled the modified New York Criteria. Radiographic severity was...

Protective effects of Croton campestris A. St-Hill in different ulcer models in rodents: Evidence for the involvement of nitric oxide and prostaglandins

Ethnopharmacological relevanceCroton campestris A. St.-Hill., popularly known as “velame do campo”, is a species native from savannah area of Northeast Brazil, which is used by traditional communities in folk medicine for a variety of health problems, especially detoxification, inflammation and gastritis. The present study investigates the possible gastric antiulcer activity of Croton campestris root extract (CCRE) and mechanisms of action underlying this effect. Materials and methodsGastric lesions were induced in mice by ethanol, acidified ethanol and indomethacin. CCRE was previously administered orally in doses ranging from 50 to 750mg/kg. Stomach lesions were measured. The involvement of Nitric Oxide (NO), prostaglandins (PGEs), ATP-dependent K+ channel and adrenergic receptor was investigated through specific inhibitors. ResultsCCRE produced significant antiulcer activity against absolute ethanol, acidified ethanol and indomethacin induced gastric lesions. The pretreatment with L-NAME (10mg/kg, p.o.), an inhibitor of nitric oxide synthesis and indomethacin (10mg/kg, s.c.), an inhibitor of prostaglandin production, reversed the antiulcer action of CCRE. ConclusionTaking together, these results suggest that the antiulcer activity of CCRE is dependent of NO and prostaglandin pathways possibly due to its ability to stimulate the synthesis of NO, and activation of endogenous prostaglandin production. Therefore, the use of CCRE in traditional Brazilian medicine against gastric disorders has a scientific basis.

Protective effect of a sesamin derivative, 3-bis (3-methoxybenzyl) butane-1, 4-diol on ischemic and hypoxic neuronal injury

BackgroundStroke is one of the leading causes of neuronal death. Sesamin is known for neuroprotection by its antioxidant and anti-inflammatory properties but it lacks blood–brain barrier (BBB) activity. A panel of sesamin derivatives was screened and 3-bis (3-methoxybenzyl) butane-1,4-diol (BBD) was selected for high BBB activity and tested for its neuroprotective effect.MethodsThe focal cerebral ischemia of Sprague–Dawley rats and hypoxia models of murine BV-2 microglia or PC12 cells under oxygen/glucose deprivation were used for in vivo and in vitro test, respectively. Lipid peroxidation and superoxide dismutase (SOD) activity from the ischemic brain were tested and reactive oxygen species (ROS), cytokine production, prostaglandin (PGE2) and related signaling pathways from hypoxic cells were examined by ELISA or Western blot assay, respectively.ResultsBBD showed a protective effect when given 90 min after the focal cerebral ischemia. It also reduced lipid peroxidation and preserved SOD activity from the ischemic brain. The mechanism of BBD was further confirmed by attenuating ROS, cytokine production, and PGE2 release from hypoxic BV-2 or PC12 cells. BBD significantly reduced hypoxia-induced c-Jun N-terminal kinases (JNK) and modulated AKT-1 and caspase-3 (survival and apoptotic pathways) in BV-2 cells, and inhibited hypoxia-induced JNK and cyclooxygenase-2 activation in PC12 cells.ConclusionsThe neuroprotective effect of BBD on ischemia/hypoxia models was involved with antioxidant and anti-inflammatory effects. The result would help the development of new CNS drug for protection of ischemia/hypoxia injury.

Prostaglandins Pathway as a Possible Biological Link Between Cancer and Major Depression

Prostaglandins Pathway as a Possible Biological Link Between Cancer and Major Depression

Estradiol and mTORC2 cooperate to enhance prostaglandin biosynthesis and tumorigenesis in TSC2-deficient LAM cells

Lymphangioleiomyomatosis (LAM) is a progressive neoplastic disorder that leads to lung destruction and respiratory failure primarily in women. LAM is typically caused by tuberous sclerosis complex 2 (TSC2) mutations resulting in mTORC1 activation in proliferative smooth muscle-like cells in the lung. The female predominance of LAM suggests that estradiol contributes to disease development. Metabolomic profiling identified an estradiol-enhanced prostaglandin biosynthesis signature in Tsc2-deficient (TSC(-)) cells, both in vitro and in vivo. Estradiol increased the expression of cyclooxygenase-2 (COX-2), a rate-limiting enzyme in prostaglandin biosynthesis, which was also increased at baseline in TSC-deficient cells and was not affected by rapamycin treatment. However, both Torin 1 treatment and Rictor knockdown led to reduced COX-2 expression and phospho-Akt-S473. Prostaglandin production was also increased in TSC-deficient cells. In preclinical models, both Celecoxib and aspirin reduced tumor development. LAM patients had significantly higher serum prostaglandin levels than healthy women. 15-epi-lipoxin-A4 was identified in exhaled breath condensate from LAM subjects and was increased by aspirin treatment, indicative of functional COX-2 expression in the LAM airway. In vitro, 15-epi-lipoxin-A4 reduced the proliferation of LAM patient-derived cells in a dose-dependent manner. Targeting COX-2 and prostaglandin pathways may have therapeutic value in LAM and TSC-related diseases, and possibly in other conditions associated with mTOR hyperactivation.

The impact of undernutrition on the activation of premature birth and prostaglandin pathway

Human preterm labor is a syndrome that may arise from different causes. Before 30 weeks of gestation, infection appears to predominate amongst these. In later gestation, premature activation of the fetal HPA axis in response to an adverse intrauterine environment, e.g. hypoxemia, undernutrition (UN) or even infection, may underlie the stimulus to prematurity. A third pathway clearly involves vascular thrombotic processes. Tests on sheep have been shown to there is a premature birth which is a significant change was associated with precocious increases in adrenocorticotrophic hormone (ACTH) and cortisol in the fetal circulation, and increased levels of mRNA encoding proopiomelanocortin (POMC) and prohormone convertase-1 (PC-1) in the pars intermedia of the fetal pituitary. It would seem that these different pathways may occur separately, or be activated to different degrees in the same patient.

Racial differences in risk of spontaneous abortions associated with periconceptional over-the-counter nonsteroidal anti-inflammatory drug exposure

PurposeNonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most common medications reported in pregnancy. NSAIDs directly impact prostaglandin pathways and have been proposed as potential risk factors for spontaneous abortions (SABs, gestation <20 weeks). SAB risk and drug response across several medications differ by race; therefore, we evaluated whether associations between NSAIDs and SAB risk differ by race. MethodsWomen were enrolled in the Right from the Start (2004–2010) prospective cohort. Data regarding over-the-counter NSAIDs up to the sixth week of pregnancy were obtained from interviews. Race was self-reported. Cox proportional hazards regression models were used to estimate the association between NSAID exposure and SAB, adjusted for confounders. ResultsAmong 2493 pregnancies, 12% were African American and 88% were Caucasian. NSAID exposure was reported by 40% (n = 124) of African Americans and 43% (n = 945) of Caucasians. Race-stratified analyses showed protection from SAB among African Americans (adjusted hazard ratio [aHR], 0.84; 95% confidence interval [CI], 0.73–0.96) but no effect in Caucasians (aHR, 1.01; 95% CI 0.88–1.16). ConclusionsOur findings suggest that risk for SAB due to over-the-counter NSAIDs in early pregnancy is modified by race. Further investigation of dose, timing in gestation, and indication may help to further reconcile the relationship between race, NSAIDs, and SAB.

Anti-inflammatory effects of fish oil in ovaries of laying hens target prostaglandin pathways

BackgroundAn effective way to control cancer is by prevention. Ovarian cancer is the most lethal gynecological malignancy. Progress in the treatment and prevention of ovarian cancer has been hampered due to the lack of an appropriate animal model and absence of effective chemo-prevention strategies. The domestic hens spontaneously develop ovarian adenocarcinomas that share similar histological appearance and symptoms such as ascites and metastasis with humans. There is a link between chronic inflammation and cancer. Prostaglandin E2 (PGE2) is the most pro-inflammatory ecoisanoid and one of the downstream products of two isoforms of cyclooxygenase (COX) enzymes: COX-1 and COX-2. PGE2 exerts its effects on target cells by coupling to four subtypes of receptors which have been classified as EP1-4. Fish oil is a source of omega-3 fatty acids (OM-3FAs) which may be effective in prevention of ovarian cancer. Our objective was to assess the potential impact of fish oil on expression of COX enzymes, PGE2 concentration, apoptosis and proliferation in ovaries of laying hens.Methods48 white Leghorn hens were fed 50, 100, 175, 375 and 700 mg/kg fish oil for 21 days. The OM3-FAs and omega-6 fatty acids contents of egg yolks were determined by Gas Chromatography. Proliferation, apoptosis, COX-1, COX-2 and prostaglandin receptor subtype 4 (EP4) protein and mRNA expression and PGE2 concentration in ovaries were measured by PCNA, TUNEL, Western blot, quantitative real-time qPCR and ELISA, respectively.ResultsConsumption of fish oil increased the incorporation of OM-3FAs into yolks and decreased both COX-1 and COX-2 protein and mRNA expression. In correlation with COXs down-regulation, fish oil significantly reduced the concentrations of PGE2 in ovaries. EP4 protein and mRNA expression in ovaries of hens was not affected by fish oil treatment. A lower dose of fish oil increased the egg laying frequency. 175 and 700 mg/kg fish oil reduced proliferation and 700 mg/kg increased apoptosis in hen ovaries.ConclusionsOur findings suggest that the lower doses of fish oil reduce inflammatory PG and may be an effective approach in preventing ovarian carcinogenesis. These findings may provide the basis for clinical trials utilizing fish oil as a dietary intervention targeting prostaglandin biosynthesis for the prevention and treatment of ovarian cancer.

Abstract C59: Estradiol and mTORC2 orchestrate to enhance prostaglandin biosynthesis andtumorigenesis in tuberous sclerosis complex

Abstract Lymphangioleiomyomatosis (LAM) is a female predominant progressive and neoplastic disorder that leads to lung destruction and respiratory failure primarily in women. LAM is typically due to TSC2 mutations resulting in mTORC1 activation in proliferative smooth muscle-like cells in the lung. The female predominance of LAM suggests that estradiol contributes to disease development. Metabolomic profiling identified estradiol-enhanced prostaglandin biosynthesis signature in Tsc2-deficient cells, both in vitro and in vivo. Estradiol increased the expression of cyclooxygenase-2 (COX-2), a rate-limiting enzyme in prostaglandin biosynthesis, which was increased at baseline in TSC2-deficient cells, and was not affected by rapamycin treatment, but decreased by Torin 1 treatment and Rictor knockdown, associated with reduction of levels phospho-Akt (S473). Prostaglandin production was also increased in TSC2-deficient cells. In preclinical models, Celecoxib or aspirin treatment suppressed tumor progression. LAM patients had significantly higher serum prostaglandin levels than healthy women. 15-epi-lipoxin-A4 was identified in exhaled breath condensate from LAM subjects and was increased by aspirin treatment, indicative of functional COX-2 expression in the LAM airway. Targeting COX-2 and prostaglandin pathways may have therapeutic value in LAM and TSC-related diseases, and possibly in other conditions associated with mTOR-hyperactivation. Citation Format: Chenggang Li, Po-Shun Lee, Xiaoxiao Gu, Yang Sun, Erik Zhang, Alfredo Csibi, Jing Li, Carmen Priolo, Yanan Guo, Chin-Lee Wu, John Blenis, Kai-Feng Xu, Elizabeth Petri Henske, Bruce Levy, David Kwiatkowski, Jane J. Yu. Estradiol and mTORC2 orchestrate to enhance prostaglandin biosynthesis andtumorigenesis in tuberous sclerosis complex. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr C59.

Flaxseed enriched diet-mediated reduction in ovarian cancer severity is correlated to the reduction of prostaglandin E2 in laying hen ovaries

Prevention of ovarian cancer is the best approach for reducing the impact of this deadly disease. The laying hen is a robust model of spontaneous ovarian cancer that recapitulates the human disease. Dietary intervention with flaxseed, the richest vegetable source of omega-3 fatty acids (OM-3FAs) and phytoestrogen lignans, demonstrate the potential for effective prevention and amelioration of ovarian cancer by targeting inflammatory prostaglandin pathways. Prostaglandin E2 (PGE2) is the most pro-inflammatory ecoisanoid and one of the downstream products of two isoforms of cyclooxygenase (COX) enzymes: COX-1 and COX-2. Our objective was to investigate the effect of flaxseed supplementation for one year on ovarian cancer and correlate its effects to expression of COX enzymes and concentrations of prostaglandins. White Leghorn hens were fed 10% flaxseed-enriched or standard diet for one year. The severity of ovarian cancer was determined by gross pathology and histology. COX-1 and COX-2 localization and protein and mRNA expression and PGE2 and PGE3 concentrations in ovaries were measured by IHC, western blot, quantitative real-time PCR and LC–MS–MS, respectively. The results demonstrated a significant reduction in late stage ovarian tumors in the flaxseed-fed hens compared with the control diet-fed hens. In correlation with decreased ovarian cancer severity, concentrations of PGE2 and expression of COX-2 were diminished in ovaries of flaxseed-fed hens. PGE3 concentrations were below the level of detection. The results demonstrated that in normal ovaries, COX-1 was localized to the granulosa cell layer surrounding the follicles and ovarian surface epithelium (OSE) whereas COX-2 protein was localized to the granulosa cell layer in the follicle. Extensive COX-1 and COX-2 protein expression was found throughout the ovarian carcinoma. Our findings suggest that the flaxseed-mediated reduction in the severity of ovarian cancer in hens is correlated to the reduction in PGE2 in the ovaries of flaxseed-fed hens. These findings may provide the basis for clinical trials of dietary intervention targeting prostaglandin biosynthesis for the prevention and treatment of ovarian cancer.

15-Deoxy-Δ12,14-Prostaglandin J2 Inhibits Macrophage Colonization by Salmonella enterica Serovar Typhimurium

15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) is an anti-inflammatory downstream product of the cyclooxygenase enzymes. It has been implicated to play a protective role in a variety of inflammatory mediated diseases, including rheumatoid arthritis, neural damage, and myocardial infarctions. Here we show that 15d-PGJ2 also plays a role in Salmonella infection. Salmonella enterica Typhimurium is a Gram-negative facultative intracellular pathogen that is able to survive and replicate inside phagocytic immune cells, allowing for bacterial dissemination to systemic sites. Salmonella species cause a wide range of morbidity and mortality due to gastroenteritis and typhoid fever. Previously we have shown that in mouse models of typhoid fever, Salmonella infection causes a major perturbation in the prostaglandin pathway. Specifically, we saw that 15d-PGJ2 production was significantly increased in both liver and feces. In this work we show that 15d-PGJ2 production is also significantly increased in macrophages infected with Salmonella. Furthermore, we show that the addition of 15d-PGJ2 to Salmonella infected RAW264.7, J774, and bone marrow derived macrophages is sufficient to significantly reduce bacterial colonization. We also show evidence that 15d-PGJ2 is reducing bacterial uptake by macrophages. 15d-PGJ2 reduces the inflammatory response of these infected macrophages, as evidenced by a reduction in the production of cytokines and reactive nitrogen species. The inflammatory response of the macrophage is important for full Salmonella virulence, as it can give the bacteria cues for virulence. The reduction in bacterial colonization is independent of the expression of Salmonella virulence genes SPI1 and SPI2, and is independent of the 15d-PGJ2 ligand PPAR-γ. 15d-PGJ2 also causes an increase in ERK1/2 phosphorylation in infected macrophages. In conclusion, we show here that 15d-PGJ2 mediates the outcome of bacterial infection, a previously unidentified role for this prostaglandin.

The Functional Role of Oxytocin in the Induction of Oocyte Meiotic Resumption in Cattle

The aim of the present study was to examine the role of oxytocin (OT) in the progesterone (P4) and prostaglandins (PGs) pathway to induce oocyte meiotic resumption. Cumulus-oocyte complexes were co-cultured with follicular hemisections for 15h to determine the effects of different doses of OT or atosiban (ATO; oxytocin receptor antagonist) on oocyte meiotic resumption. In another experiment, we examined the effect of the interaction between P4, OT and PGs on the regulatory cascade of the oocyte meiotic resumption. Oxytocin at 1μm was effective in inducing meiotic resumption in oocytes co-cultured with follicular cells (84.0%), not differing from the positive control group (74.4%). Atosiban inhibited in a dose-dependent manner the positive effect of OT on the meiotic resumption (27.6% metaphase I with 10μm of ATO, which did not differ from the 25.5% of the negative control group). Furthermore, a third experiment showed that P4 was able to induce oocyte meiotic resumption, which was inhibited by ATO. However, the OT positive effect was not blocked by mifepristone (P4 antagonist), but was inhibited by indomethacin (a non-selective PTGS2 inhibitor). Collectively, these data suggest a sequential role of P4, OT and PGs in the induction of oocyte meiotic resumption.

Role of prostaglandin pathways in radiotherapy-induced mucositis.

e20509 Background: Pathways associated with proinflammatory molecules are upregulated in oral mucositis. Lalla (Support Care Cancer 18:95, 2010) found an association between mucositis pain scores, tissue COX-1, and salivary prostaglandins in 4 patients receiving dose-dense chemotherapy. We investigated whether similar changes would be seen with radiotherapy (XRT)-induced mucositis. Methods: Patients receiving XRT including the oropharynx were evaluated at 4 time points, before XRT, midway through XRT, end of XRT, and 1 month after XRT. Subjective report of pain and objective mucositis scores were recorded. Patients also provided a 5-minute stimulated saliva specimen at each time point collected on ice with a protease inhibitor cocktail. Proteins were estimated using a Bradford assay. Prostaglandins were measured using ELISA assays. Results: 8 evaluable patients entered the study, including 7 male/1 female, median age 60 (range 48-66), primary site (oropharynx 1, unknown primary 1, base of tongue 3, tonsil 1, tongue 1, supraglottis 1), median XRT 7000 rads (range 6000-7200 rads), concomitant chemotherapy (cisplatin 7, none 1), histology (squamous 7, mucoepidermoid 1). Pain and mucositis scores increased during XRT and improved at 1 month after XRT. No increase in COX-2 levels was seen. Salivary PGD2, PGE2, and PGF2 increased from baseline with the greatest increase 1 month after XRT. There was a significant time effect for PGF2 (p=0.028) and marginal time effects for PGD2 (p=0.107) and PGE2 (p=0.069). Conclusions: Increased salivary prostaglandins are seen during and after XRT-induced oral mucositis, suggesting a role for proinflammatory mediators and providing a possible therapeutic target. Clinical trial information: NCT01252498. [Table: see text]

Transcriptomic profiling of progesterone in the male fathead minnow (Pimephales promelas) testis

P4 is a hormone with diverse functions that include roles in reproduction, growth, and development. The objectives of this study were to examine the effects of P4 on androgen production in the mature teleost testis and to identify molecular signaling cascades regulated by P4 to improve understanding of its role in male reproduction. Fathead minnow (FHM) testis explants were treated in vitro with two concentrations of P4 (10−8 and 10−6M) for 6 and 12h. P4 significantly increased testosterone (T) production in the FHM testis but did not affect 11-ketotestosterone. Gene network analysis revealed that insulin growth factor (Igf1) and tumor necrosis factor receptor (Tnfr) signaling was significantly depressed with P4 treatment after 12h. There was also a 20% increase in a gene network for follicle-stimulating hormone secretion and an 18% decrease in genes involved in vasopressin signaling. Genes in steroid metabolism (e.g. star, cyp19a, 11bhsd) were not significantly affected by P4 treatments in this study, and it is hypothesized that pre-existing molecular machinery may be more involved in the increased production of T rather than the de novo expression of steroid-related transcripts and receptors. There was a significant decrease in prostaglandin E synthase 3b (cytosolic) (ptges3b) after treatment with P4, suggesting that there is cross talk between P4 and prostaglandin pathways in the reproductive testis. P4 has a role in regulating steroid production in the male testis and may do so by modulating gene networks related to endocrine pathways, such as Igf1, Tnfr, and vasopressin.

Expression of enzymes and receptors of leukotriene pathway genes in equine endometrium during the estrous cycle and early pregnancy

The aims of the present study were to elucidate the expression profiles of leukotriene (LT) pathway mRNA transcription and to determine the possible interaction of LT and prostaglandin (PTG) pathways genes in equine endometrium during the estrous cycle and early pregnancy. Endometrial biopsies were obtained from mares on the day of ovulation (d0), at late diestrous (LD, n = 4), and after luteolysis in the estrus phase (AL, n = 4) of the cycle. Biopsies were also taken on Days 14 (P14; n = 4), 18 (P18, n = 4), and 22 (P22, n = 4) during early pregnancy that were comparable days to cyclic sampling days. A mixed model was fitted on the normalized relative mRNA levels, quantified by qPCR in duplicate, and least significant difference test was employed to detect significantly different group(s). In addition, to determine the degree of contribution of each gene to separation of treatment groups, the multivariate projection method partial least square regression discriminant analysis was used. The expression of 5-lipoxygenase mRNA was greater on d0 and LD, declined at AL, and was suppressed by early pregnancy. Leukotriene A4 hydrolase mRNA expression increased at LD and during early pregnancy, but was significantly greater at LD compared with P14. The expression of LT C4 synthase mRNA was only induced at LD. Cysteinyl leukotriene receptors (CysLT1 and CysLT2) mRNA expressions were decreased by both cyclic changes and early pregnancy, whereas 5-lipoxygenase-activating protein and B leukotriene receptor mRNA expressions were not affected by early pregnancy or stages of the estrous cycle. Partial least square discriminant analysis suggests that LT and PTG pathway enzymes and receptors appear to behave similarly in terms of mRNA expression. In conclusion, the expression profiles of LT pathway genes are demonstrated in equine endometrium for the first time by the present study, and the present data suggest that LT pathway mRNA transcriptions are tightly regulated during early pregnancy in mares.

Hormonal Therapy Deregulates Prostaglandin-Endoperoxidase Synthase 2 (PTGS2) Expression in Endometriotic Tissues

Endometriosis is a common gynecologic condition characterized by an important inflammatory process mediated by the prostaglandin pathway. Oral contraceptives are the treatment of choice for symptomatic endometriotic women. However the effects of oral contraceptives use and prostaglandin pathway in endometriotic women are actually still unknown. To investigate the expression of prostaglandin pathway key genes in endometriotic tissue, affected or not by hormonal therapy, as compared with healthy endometrial tissue. This was a comparative laboratory study. This study was conducted in a tertiary-care university hospital. Seventy-six women, with (n = 46) and without (n = 30) histologically proven endometriosis. Prostaglandin-endoperoxidase synthase (PTGS)1, PTGS2, prostaglandin E receptor (PTGER)1, PTGER2, PTGER3, and PTGER4 mRNA levels in endometrium of disease-free women and in eutopic and ectopic endometrium of endometriosis-affected women. PTGS2 expression was further investigated by immunohistochemistry, using specific monoclonal antibodies. PTGS2 expression was analyzed at mRNA and protein levels and correlated with taking hormonal treatment. PTGS2 expression was significantly increased in eutopic and ectopic endometrium as compared with healthy tissue (induction of 9.6- and 6.3-fold, respectively; P = .001). PTGS2 immunoreactivity increased gradually from normal endometrium to eutopic and ectopic endometrium (h-score of 96.7 ± 55.0, 128.3 ± 66.1, and 226.7 ± 62.6, respectively, P < .001). PTGER2, PTGER3, and PTGER4 expression increased significantly and gradually from normal to eutopic and ectopic endometrium, whereas PTGER1 remained unchanged. Patients under hormonal treatment had a higher PTGS2 expression at transcriptional and protein levels as compared with those without treatment (P = .002 and P = .025, respectively). Prostaglandin pathway is strongly deregulated in eutopic and ectopic endometrium of women suffering from endometriosis for the benefit of an increased PTGS2 expression. We show for the first time that hormonal treatment appears to enhance even more PTGS2 expression. These results contribute to explain why medical treatment could fail to control endometriosis progression.

Immune mechanisms in epileptogenesis.

Epilepsy is a chronic brain disorder that affects 1% of the human population worldwide. Immune responses are implicated in seizure induction and the development of epilepsy. Pre-clinical and clinical evidence have accumulated to suggest a positive feedback cycle between brain inflammation and epileptogenesis. Prolonged or recurrent seizures and brain injuries lead to upregulation of proinflammatory cytokines and activated immune responses to further increase seizure susceptibility, promote neuronal excitability, and induce blood–brain barrier breakdown. This review focuses on the potential role of innate and adaptive immune responses in the pathogenesis of epilepsy. Both human studies and animal models that help delineate the contributions of brain inflammation in epileptogenesis will be discussed. We highlight the critical role of brain-resident immune mediators and emphasize the contribution of brain-infiltrating peripheral leukocytes. Additionally, we propose possible immune mechanisms that underlie epileptogenesis. Several proinflammatory pathways are discussed, including the interleukin-1 receptor/toll-like receptor signaling cascade, the pathways activated by damage-associated molecular patterns, and the cyclooxygenase-2/prostaglandin pathway. Finally, development of better therapies that target the key constituents and processes identified in these mechanisms are considered, for instance, engineering antagonizing agents that effectively block these pathways in an antigen-specific manner.

Age dependent increase in prostaglandin pathway coincides with onset of ovarian cancer in laying hens

Chronic inflammation has been linked to cancer. Prostaglandin E2 (PGE2) is the most pro-inflammatory lipid and one of the downstream products of 2 isoforms of cyclooxygenase (COX) enzymes: COX-1 and COX-2. Ovarian cancer is the most lethal gynecological malignancy and mainly occurs in older women. The factors that contribute to the correlation of age and ovarian cancer are unknown. The purpose of this study was to examine the expression of COX enzymes and PGE2 levels in ovaries and correlate them to ovarian cancer and aging. White Leghorn hens aged 1, 1.5, 2, 2.5, 3 and 3.5 years were used. The incidence of ovarian cancer was determined by gross pathology and histology. COX-1 and COX-2 protein and mRNA expression and PGE2 concentrations in ovaries were measured using Western blot, quantitative real-time PCR and ELISA, respectively. Our results indicated an increase in ovarian cancer incidence and expression of both COX enzymes in ovaries of older hens. In correlation with ovarian cancer incidence and COX enzymes expression, PGE2 concentrations were elevated with age. Ovaries with tumor had elevated COX-1 expression and PGE2 concentration compared to normal ovaries. Our findings suggest that the up-regulation of COX enzymes with age is the main contributing factor in the age associated increase in PGE2. Furthermore, elevated PGE2 in ovaries of hens concomitant with age suggests its important role in early stages of ovarian carcinogenesis. These finding may provide the basis for clinical trials utilizing COX specific inhibitors or dietary intervention targeting prostaglandin biosynthesis for the prevention and treatment of ovarian cancer.

The connection between lymphangiogenic signalling and prostaglandin biology: A missing link in the metastatic pathway

Substantial evidence supports important independent roles for lymphangiogenic growth factor signaling and prostaglandins in the metastatic spread of cancer. The significance of the lymphangiogenic growth factors, vascular endothelial growth factor (VEGF)-C and VEGF-D, is well established in animal models of metastasis, and a strong correlation exits between an increase in expression of VEGF-C and VEGF-D, and metastatic spread in various solid human cancers. Similarly, key enzymes that control the production of prostaglandins, cyclooxygenases (COX-1 and COX-2, prototypic targets of Non-steroidal anti-inflammatory drugs (NSAIDs)), are frequently over-expressed or de-regulated in the progression of cancer. Recent data have suggested an intersection of lymphangiogenic growth factor signaling and the prostaglandin pathways in the control of metastatic spread via the lymphatic vasculature. Furthermore, this correlates with current clinical data showing that some NSAIDs enhance the survival of cancer patients through reducing metastasis. Here, we discuss the potential biochemical and cellular basis for such anti-cancer effects of NSAIDs through the prostaglandin and VEGF signaling pathways.

Lipopolysaccharide-induced murine embryonic resorption involves nitric oxide-mediated inhibition of the NAD+-dependent 15-hydroxyprostaglandin dehydrogenase

The initial inactivation of prostaglandins (PGs) is mediated by 15-hydroxyprostaglandin dehydrogenase (15-PGDH). PGs are potent mediators of several biological processes, including inflammation and reproduction. In uterus, PGs play a key role in infection-induced pregnancy loss, in which concentration of this mediator increased. This process is accompanied with the induction of nitric oxide synthase expression and a marked increase in uterine levels of nitric oxide. There is no information concerning nitric oxide contribution to potential changes in PG catabolism, but experimental evidence suggests that nitric oxide modulates PG pathways. The specific objectives of the study were to evaluate the protein expression of HPGD (15-PGDH) and to characterize the nitric oxide-dependent regulation of this enzyme in a model of lipopolysaccharide (LPS)-induced embryonic resorption. Results show that LPS decreased HPGD protein expression and augmented PGE synthase activity; therefore, PGE₂ levels increased in uterus in this inflammatory condition. Just as LPS, the treatment with a nitric oxide donor diminished HPGD protein expression in uterine tissue. In contrast, the inhibition of nitric oxide synthesis both in control and in LPS-treated mice increased 15-PGDH levels. Also, we have found that this enzyme and PGE₂ levels are not modulated by peroxynitrite, an oxidant agent derived from nitric oxide. This study suggests that LPS and nitric oxide promote a decrease in the ability of the uterus for PG catabolism during bacterially triggered pregnancy loss in mice.