Biological functions of 12(S)-hydroxyheptadecatrienoic acid as a ligand of leukotriene B4 receptor 2

Although 12(S)-hydroxyheptadecatrienoic acid (12-HHT) is an abundant fatty acid, it is long considered a byproduct of thromboxane A₂ production. We identified a leukotriene B₄ receptor 2 (BLT2)-specific agonistic activity in lipid extracts from rat small intestine, and mass spectrometric analysis of partially purified lipids containing BLT2 agonistic activity revealed that 12-HHT is an endogenous ligand of BLT2. In a dextran sulfate sodium (DSS)-induced inflammatory colitis model, BLT2-deficient mice exhibited enhanced intestinal inflammation, possibly due to impaired epithelial barrier function. In a skin wound healing model, BLT2-deficient mice exhibited delayed wound healing via dampened keratinocyte migration. BLT2 also accelerates corneal wound healing, and eye drops containing a non-steroidal anti-inflammatory drug (NSAID) inhibit the production of 12-HHT, resulting in delayed corneal wound healing. Furthermore, BLT2 is expressed in pulmonary epithelial type II cells and vascular endothelial cells in the mouse lung, and BLT2-deficient mice are more susceptible to lung damage by pneumolysin. In this review, we summarize the identification and characterization of 12-HHT as a ligand for BLT2 and discuss recent research on the physiological and pathophysiological roles of the 12-HHT-BLT2 axis. Some side effects of NSAIDs such as delayed wound healing may be caused by reduced 12-HHT production rather than diminished production of prostaglandins.

Variability in analgesic response to non-steroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used agents for the treatment of acute and chronic pain. However, it has long been recognized that there is substantial inter-individual variability in the analgesic response to NSAIDs, reflecting the complex interplay between mechanisms of pain, differences between distinct NSAIDs, and patient-specific factors such as genetic variation. This review summarizes the current knowledge regarding how these factors contribute to variability in the analgesic response to NSAIDs.

Evaluation of anti-inflammatory and immunomodulatory effects of Premna integrifolia extracts and assay-guided isolation of a COX-2/5-LOX dual inhibitor

Premna integrifolia (Agnimantha brihat) is a traditional medicinal plant with a prominent place in Ayurveda, Siddha and Unani systems of medicine. In this study we have evaluated the anti-inflammatory and immunomodulatory properties of the Premna integrifolia root extracts employing cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and 5-lipoxygenase (5-LOX) enzyme-based assays, lymphocyte proliferation assay, pro-and anti-inflammatory cytokines measurement. Petroleum ether extract (PEE) of Premna integrifolia showed potent inhibition of COX-2 and 5-LOX with IC₅₀ values of 6.15 μg/mL and 11.33 μg/mL respectively. In in vitro studies on RAW 264.7 cell line, PEE showed inhibition in the formation of nitric oxide (NO), pro-inflammatory cytokines (IL-1β, IL-6), prostaglandin E₂ (PGE₂) production, induction of anti-inflammatory cytokine (IL-2) and down-regulation of expression of COX-2, 5-LOX, TNF-α, IL-1β and iNOS. PEE also significantly reduced carrageenan-induced paw edema in mouse model of inflammation. Further, attempts in isolating the active principle(s) involved in these anti-inflammatory effects of PEE by separation on RP-HPLC resulted in the isolation of four active peaks, H1, H2, H3 and H5, inhibiting COX-1, COX-2 and 5-LOX, out of which H3 was identified as 6- hydroxy salvinolone (6-HS). Present findings reveal that PEE of roots of Premna integrifolia exhibits potent anti-inflammatory and immunomodulatory activities, which could form a potential source for development of anti-inflammatory drugs. 6-HS, a COX-2/5-LOX dual inhibitor along with other lead molecules isolated from PEE of Premna integrifolia may form lead molecules for the development of COX-LOX dual inhibitors.

Anti-platelet treatments in cancer: Basic and clinical research

Over the past few decades the central role that platelets play in cancer development and progression, and especially in metastasis, has been elucidated. The molecular mechanisms responsible for initiating and mediating tumor cell-induced platelet aggregation and secretion have been largely unravelled. Considerable mechanistic insight into how platelets contribute to tumor angiogenesis, immunoevasion and cancer cell invasion have been clarified and, consequently, platelets have been identified as potential new drug targets for cancer therapy. This article gives an overview of the platelet-targeted pharmacologic approaches that have been attempted in the prevention of cancer development, progression and metastasis, including the application of antiplatelet drugs currently used for cardiovascular disease and of new and novel strategies.

Hepatic injury induced by thioacetamide causes aortic endothelial dysfunction by a cyclooxygenase-dependent mechanism

Liver cirrhosis is associated with a wide range of cardiovascular abnormalities including hyperdynamic circulation and cirrhotic cardiomyopathy. The pathogenic mechanisms of these cardiovascular changes are multifactorial and include vascular dysregulations.

AIM

The present study tested the hypothesis that the systemic vascular hyporesponsiveness in thioacetamide (TAA)-induced liver injury model is dependent on nitric oxide (NO) and cyclooxygenase (COX) derivatives.

MAIN METHODS

Wistar rats were treated with TAA for eight weeks to induce liver injury.

KEY FINDINGS

The maximal contractile response in concentration-effect curves to phenylephrine was decreased in aorta from TAA-treated rats, but no differences were found in aorta without endothelium, suggesting an endothelium-dependent mechanism in decreased contractile response. There was no difference in the contractile response with and without L-NAME (N(ω)-nitro-l-arginine methyl ester) in rats with liver injury, showing that the TAA treatment impairs NO synthesis. Pre-incubation of the aorta with indomethacin, a COX-inhibitor, normalized the reduced contractile response to phenylephrine in arteries from TAA group. Also, COX-2 and iNOS (inducible nitric oxide syntase) protein expression was increased in aorta from TAA group compared to control group. Animals submitted to TAA treatment had a reduction in systolic blood pressure. Our findings demonstrated that liver injury induced by TAA caused a decrease in aortic contractile response by a COX-dependent mechanism but not by NO release. Also, it was demonstrated an inflammatory process in the aorta of TAA-treated rats by increased expression of COX-2 and iNOS.

SIGNIFICANCE

Therefore, there is an essential contribution of COX-2 activation in extra-hepatic vascular dysfunction and inflammation present in cirrhosis induced by TAA.

Ketogenic diets attenuate cyclooxygenase and lipoxygenase gene expression in multiple sclerosis

Background

Adapted ketogenic diet (AKD) and caloric restriction (CR) have been suggested as alternative therapeutic strategies for inflammatory, hyperproliferative and neurodegenerative diseases. Pro-inflammatory eicosanoids have been implicated in the pathogenesis of multiple sclerosis since they augment vascular permeability and induce leukocyte migration into the brain. We explored the impact of ketogenic diets on gene expression of biosynthetic enzymes for pro- (ALOX5, COX1, COX2) and anti-inflammatory (ALOX15) eicosanoids in patients with relapsing-remitting multiple sclerosis.

Methods

60 adults were prospectively recruited for this six months randomized controlled trial and the impact of dietary treatment on the Multiple Sclerosis Quality of Life-54 index (ClinicalTrials.gov (NCT01538355) has previously been published. Here we explored 24 patients (8 controls, 5 on CR and 11 on AKD). For statistical analysis we combined the two diet groups to a single pooled treatment group.

Findings

Inter-group comparison indicated that expression of the pro-inflammatory ALOX5 in the pooled treatment group was significantly (p < 0.05) reduced when compared with the control group. Moreover, intra-group comparison (same individuals before and after dietary treatment) suggested significantly impaired expression of other pro-inflammatory enzymes, such as COX1 (p < 0.001) and COX2 (p < 0.05). Finally, pretreatment cross-group analysis revealed a significant positive correlation between expression of pro-inflammatory ALOX5 and COX2 and an inverse correlation of ALOX5 and COX1 expression with the MSQoL-54 index.

Interpretation

Ketogenic diets can reduce the expression of enzymes involved in the biosynthesis of pro-inflammatory eicosanoids. Pharmacological interference with eicosanoid biosynthesis might constitute a strategy supplementing current therapeutic approaches for MS.

Sub-chronic celecoxib prevents soluble beta amyloid-induced depressive-like behaviour in rats

BACKGROUND

Depression and Alzheimer's disease (AD) are co-morbid conditions. Neuropsychiatric symptoms have been reported as prodromal symptoms of AD-like dementia and soluble forms of beta amyloid peptide (Aβ), the main constituent of insoluble plaques typical of AD brains, have been implicated in such an effect. We have previously shown that intracerebral injection of Aβ can evoke a depressive-like state in rats, accompanied by neurochemical and neuroendocrine alterations reminiscent of depressive symptoms in humans. AD and depression are crucially linked by neuroinflammation and cyclooxygenase II (COX-2) enzyme involvement is an intriguing field of research. Indeed, its pharmacological inhibition has shown both antidepressant and Aβ modulating effects.

METHODS

Male rats were exposed to sub-chronic celecoxib (15 mg/kg/day sc for 8 days), a selective COX-2 inhibitor or vehicle (saline), starting from the day before central intracerebroventricular injection of Aβ peptide (5µL of 4 µM solution or vehicle for sham). Animals were tested for depressive-like behaviour by using the forced swimming test paradigm and prefrontal serotonin (5-HT) content and plasma Aβ levels were further evaluated.

RESULTS

We found that celecoxib treatment prevented the pro-depressive effects induced by Aβ. Moreover, it also prevented the reduction in 5-HT content in prefrontal cortex of Aβ-treated rats and decreased their plasma Aβ levels.

CONCLUSIONS

Taken together, our data indicate that celecoxib could be a suitable pharmaceutical tool for the treatment of depressive state related to increased Aβ levels.

Prostaglandin D2/J2 signaling pathway in a rat model of neuroinflammation displaying progressive parkinsonian-like pathology: potential novel therapeutic targets

BACKGROUND

Prostaglandins are products of the cyclooxygenase pathway, which is implicated in Parkinson's disease (PD). Limited knowledge is available on mechanisms by which prostaglandins contribute to PD neurodegeneration. To address this gap, we focused on the prostaglandin PGD2/J2 signaling pathway, because PGD2 is the most abundant prostaglandin in the brain, and the one that increases the most under pathological conditions. Moreover, PGJ2 is spontaneously derived from PGD2.

METHODS

In this study, we determined in rats the impact of unilateral nigral PGJ2-microinfusions on COX-2, lipocalin-type PGD2 synthase (L-PGDS), PGD2/J2 receptor 2 (DP2), and 15 hydroxyprostaglandin dehydrogenase (15-PGDH). Nigral dopaminergic (DA) and microglial distribution and expression levels of these key factors of the prostaglandin D2/J2 pathway were evaluated by immunohistochemistry. PGJ2-induced motor deficits were assessed with the cylinder test. We also determined whether oral treatment with ibuprofen improved the PD-like pathology induced by PGJ2.

RESULTS

PGJ2 treatment induced progressive PD-like pathology in the rats. Concomitant with DA neuronal loss in the substantia nigra pars compacta (SNpc), PGJ2-treated rats exhibited microglia and astrocyte activation and motor deficits. In DA neurons, COX-2, L-PGDS, and 15-PGDH levels increased significantly in PGJ2-treated rats compared to controls, while DP2 receptor levels were unchanged. In microglia, DP2 receptors were basically non-detectable, while COX-2 and L-PGDS levels increased upon PGJ2-treatment, and 15-PGDH remained unchanged. 15-PGDH was also detected in oligodendrocytes. Notably, ibuprofen prevented most PGJ2-induced PD-like pathology.

CONCLUSIONS

The PGJ2-induced rat model develops progressive PD pathology, which is a hard-to-mimic aspect of this disorder. Moreover, prevention of most PGJ2-induced PD-like pathology with ibuprofen suggests a positive feedback mechanism between PGJ2 and COX-2 that could lead to chronic neuroinflammation. Notably, this is the first study that analyzes the nigral dopaminergic and microglial distribution and levels of factors of the PGD2/J2 signaling pathway in rodents. Our findings support the notions that upregulation of COX-2 and L-PGDS may be important in the PGJ2 evoked PD-like pathology, and that neuronal DP2 receptor antagonists and L-PGDS inhibitors may be novel pharmacotherapeutics to relieve neuroinflammation-mediated neurodegeneration in PD, circumventing the adverse side effects of cyclooxygenase inhibitors.

Eicosanoid signaling in carcinogenesis of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related death in the USA. It is of practical importance to identify novel therapeutic targets of CRC to develop new anti-cancer drugs and to discover novel biomarkers of CRC to develop new detection methods. Eicosanoids, which are metabolites of polyunsaturated fatty acids produced by cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) enzymes, are important lipid-signaling molecules involved in the regulation of inflammation and tumorigenesis. Substantial studies have shown that the profiles of eicosanoids are deregulated in CRC, and the enzymes, metabolites, and receptors in the eicosanoid signaling cascade play critical roles in regulating colonic inflammation and colon tumorigenesis. In this review, we discuss the roles of the COX, LOX, and CYP pathways in the carcinogenesis of CRC.

Characterization of the retina-induced relaxation in mice

PURPOSE

The retinal relaxing factor (RRF) is a continuously released factor from the retina that causes vasorelaxation, the identity and potential role in physiology of which remain largely unknown. Experiments were performed to find out whether the RRF-induced relaxation is influenced by serotonin, glutamate, L-cysteine, the cytochrome P450 pathway, the cyclooxygenase pathway, or oxidative stress. In addition, the sensitivity of retinal and non-retinal arteries towards the RRF was compared.

METHODS

In vitro tension measurements were performed on isolated mouse femoral or bovine retinal arteries to study the vasorelaxing effect of the RRF, induced by mouse or bovine retinas.

RESULTS

The presence of serotonin, glutamate, or L-cysteine did not alter the RRF-induced relaxation. Increasing oxidative stress by hydroquinone and diethyldithiocarbamic acid sodium salt enhanced the RRF response. Inhibition of the cytochrome P450 or the cyclooxygenase pathway did not cause any alteration. Surprisingly, the RRF-induced relaxation was enhanced by the presence of flufenamic acid or carbenoxolone. Furthermore, bringing retinal tissue in close contact with retinal or non-retinal arteries induced comparable relaxations.

CONCLUSIONS

Serotonin, glutamate, L-cysteine, the cytochrome P450, and the cyclooxygenase pathway do not influence the RRF-induced relaxation and the RRF-induced relaxation seems to be resistant to oxidative stress. The mechanism responsible for the enhanced RRF-induced relaxation in the presence of flufenamic acid or carbenoxolone remains elusive and the RRF does not show more effectivity on retinal arteries.

Oil from the fruits of Pterodon emarginatus Vog.: A traditional anti-inflammatory. Study combining in vivo and in silico

ETHNOBOTANICAL RELEVANCE

The oil obtained from the fruits of Pterodon emarginatus Vog. (OPe) is used orally and topically, in traditional medicine for some purposes, such as acute and chronic inflammatory states as rheumatoid arthritis.

MATERIALS AND METHODS

In this work, the anti-inflammatory activity of the OPe was demonstrated based on several animal models and presented an in silico study based on the 6α,7β-dihydroxy-vouacapan-17β-oic acid (DHVA) majority compound of the OPe to evaluate the interaction this compound, with cyclooxygenase-2 (COX-2) in 4COX (Mus musculus) and 5KIR (Homo sapiens) and molecular dynamics simulation.

RESULTS

The OPe (498 mg/kg, p.o) significantly inhibited (p < 0.05, Student t-test) the primary and secondary reactions of arthritis by Freund's Complete Adjuvant (FCA) and in dermatitis induced by croton oil in mice, OPe inhibited peak of edema. In vascular permeability test in rats, the treatment with OPe was able to block the response to PGE₂, serotonin, and bradykinin (p < 0.05, Student t-test). In the writhing test in mice, the OPe at doses of 498 and 980 mg/kg (p.o) produced inhibition of 73% and 92%, respectively, and was not significantly effective in the hot plate test. In the evaluation of the potency in relation to gastric injury (gastric ulcer induced by stress) and combined assay in the assessment of anti-inflammatory potency and gastric damage, it was observed that indomethacin (10 mg/kg, p.o.) inhibited carrageenan edema by 51% and produced a higher number of gastric lesions when compared to the group treated with OPe, where only areas of hyperemia were observed, without the occurrence of ulcerative lesion, and which inhibited the edema by 47%. In the in silico study, it was found that the DHVA is capable of binding to two organisms (4COX - Mus musculus and 5KIR - Homo sapiens), however, with higher binding affinity to the organism Homo sapiens.

CONCLUSIONS

As expected, all tested ligands were capable of forming hydrogen interactions with residues at their respective binding sites, but the DHVA ligand was capable of creating slightly more hydrogen bonds when docked to either 4COX or 5KIR than the other tested ligands, thus demonstrating the participation of this compound in the anti-inflammatory and antialgic responses observed in the in vivo assays as a COX-2 inhibitor. Therefore, the results obtained support the traditional use of OPe for inflammatory and gastric problems.

Prostaglandins in asthma and allergic diseases

Prostaglandins are synthesized through the metabolism of arachidonic acid via the cyclooxygenase pathway. There are five primary prostaglandins, PGD₂, PGE₂, PGF₂, PGI₂, and thromboxane B₂, that all signal through distinct seven transmembrane, G-protein coupled receptors. The receptors through which the prostaglandins signal determines their immunologic or physiologic effects. For instance, the same prostaglandin may have opposing properties, dependent upon the signaling pathways activated. In this article, we will detail how inhibition of cyclooxygenase metabolism and regulation of prostaglandin signaling regulates allergic airway inflammation and asthma physiology. Possible prostaglandin therapeutic targets for allergic lung inflammation and asthma will also be reviewed, as informed by human studies, basic science, and animal models.

Cyclooxygenases and lipoxygenases are used by the fungus Podospora anserina to repel nematodes

Oxylipins are secondary messengers used universally in the living world for communication and defense. The paradigm is that they are produced enzymatically for the eicosanoids and non-enzymatically for the isoprostanoids. They are supposed to be degraded into volatile organic compounds (VOCs) and to participate in aroma production. Some such chemicals composed of eight carbons are also envisoned as alternatives to fossil fuels. In fungi, oxylipins have been mostly studied in Aspergilli and shown to be involved in signalling asexual versus sexual development, mycotoxin production and interaction with the host for pathogenic species. Through targeted gene deletions of genes encoding oxylipin-producing enzymes and chemical analysis of oxylipins and volatile organic compounds, we show that in the distantly-related ascomycete Podospora anserina, isoprostanoids are likely produced enzymatically. We show the disappearance in the mutants lacking lipoxygenases and cyclooxygenases of the production of 10-hydroxy-octadecadienoic acid and that of 1-octen-3-ol, a common volatile compound. Importantly, this was correlated with the inability of the mutants to repel nematodes as efficiently as the wild type. Overall, our data show that in this fungus, oxylipins are not involved in signalling development but may rather be used directly or as precursors in the production of odors against potential agressors.

SIGNIFICANCE

We analyzse the role in inter-kingdom communication of lipoxygenase (lox) and cyclooxygenase (cox) genes in the model fungus Podospora anserina. Through chemical analysis we define the oxylipins and volatile organic compounds (VOCs)produce by wild type and mutants for cox and lox genes, We show that the COX and LOX genes are required for the production of some eight carbon VOCs. We show that COX and LOX genes are involved in the production of chemicals repelling nematodes. This role is very different from the ones previously evidenced in other fungi.

Hydroxyobtustyrene protects neuronal cells from chemical hypoxia-induced cell death

Hydroxyobtustyrene is a derivative of cinnamyl phenol isolated from Dalbergia odorifera T. Chen. The heartwood, known as 'JiangXiang', is a traditional Chinese medicine. Previous studies showed that hydroxyobtustyrene inhibited the biosynthesis of prostaglandins, which are mediators of neuronal cell death in ischemia. However, it currently remains unclear whether hydroxyobtustyrene protects neurons against ischemic stress. In the present study, we investigated the protective effects of hydroxyobtustyrene against sodium cyanide (NaCN)-induced chemical ischemia. Hippocampal neurons were cultured from the cerebral cortices of E18 Wistar rats. The effects of hydroxyobtustyrene on neuronal survival and trophic effects were estimated under lower and higher cell density conditions. After the treatment of 1 mM NaCN with or without hydroxyobtustyrene, an MTT assay, Hoechst staining, and immunocytochemistry for cyclooxygenase (COX)-2 were performed. Hydroxyobtustyrene increased cell viability under lower, but not normal density conditions. Neither the neurite number nor the length was influenced by hydroxyobtustyrene. NaCN significantly decreased viability and increased fragmentation in cell nuclei, and these changes were prevented by hydroxyobtustyrene. Moreover, NaCN increased the number of COX-2-positive neurons, and this was significantly prevented by the co-treatment with hydroxyobtustyrene. Therefore, hydroxyobtustyrene protected cultured hippocampal neurons against NaCN-induced chemical ischemia, which may be mediated by the inhibition of COX-2 production.

Synthesis, biological evaluation and docking study of 1,3,4-thiadiazole-thiazolidinone hybrids as anti-inflammatory agents with dual inhibition of COX-2 and 15-LOX

Selective inhibition of both cyclooxygenase-2 (COX-2) and 15-lipooxygenase (15-LOX) may provide good strategy for alleviation of inflammatory disorders while minimizing side effects associated with current anti-inflammatory drugs. The present study describes the synthesis, full characterization and biological evaluation of a series of thiadiazole-thiazolidinone hybrids bearing 5-alk/arylidene as dual inhibitors of these enzymes. Our design was based on merging pharmacophores that exhibit portent anti-inflammatory activities in one molecular frame. 5-(4-hydroxyphenyl)-1,3,4-thiadiazol-2-amine (3) was efficiently synthesized, chloroacetylated and cyclized to give the key 4-thiazolidinone (5). Knovenagel condensation of 5 with different aldehydes afforded the final compounds 6a-m, 7, 8 and 9. These compounds were subjected to in vitro COX-1/COX-2, 15-LOX inhibition assays. Compounds (6a, 6f, 6i, 6l, 6m and 9) with promising potency (IC₅₀ = 70-100 nM) and selectivity index (SI = 220-55) were further tested for in vivo anti-inflammatory activity and effect on gastric mucosa. The most promising compound (6l) inhibits COX-2 enzyme at a nanomolar concentration (IC₅₀ = 70 nM, SI = 220) with simultaneous inhibition of 15-LOX (IC₅₀ = 11 µM). These results are comparable to the potency and selectivity of the standard drugs of both enzymes; celecoxib (COX-2 IC₅₀ = 49 nM, SI = 308) and zileuton (15-LOX IC₅₀ = 15 µM) in one construct. Interestingly three compounds (6a, 6l and 9) exhibited equivalent to or even higher than that of celecoxib in vivo anti-inflammatory activity at 3 h interval with good GIT safety profile. Molecular docking study conferred binding sites of these compounds on COX-2 and 15-LOX. Such type of compounds would represent valuable leads for further investigation and derivatization.

Previously undisclosed bioactive sterols from corbiculid bivalve clam Villorita cyprinoides with anti-inflammatory and antioxidant potentials

The estuarine Corbiculid bivalve black clam, Villorita cyprinoides collected from the Southwestern coastline regions of Arabian Sea are significant resources of nutritional and bioactive pluralities. The purification of ethyl acetate:methanol (EtOAc:MeOH) extract of V. cyprinoides characterized a previously undisclosed specialized abeo-pregnane-type sterol derivative 19 (10 → 5) abeo-20-methyl-pregn-10-en-3β-yl-hex-(3'E)-enoate (1) along with two cholestenols (22E),(24¹E)-24¹,24²-dihomocholesta-5,22,24¹-trien-3β-ol (2) and (22E)-24¹-homocholesta-5,22-dien-(3β,24¹β)-diol (3). These compounds were characterized by comprehensive spectroscopic investigations. The anti-inflammatory (anti-cyclooxygenase-1, 2/5-lipoxidase) activities of 1 were considerably higher (IC₅₀ < 1.10 mg/mL) than 2-3 (IC₅₀ > 1.10 mg/mL). These studied compounds registered greater selectivity indices (∼1.03) against cyclooxygenase-2 than cyclooxygenase-1. The antioxidant property of abeo-pregnane-type sterol as determined by in vitro 2,2'-azino-bis-(3-ethyl-benzthiazoline-6-sulfonic acid) quenching potential was significantly greater (IC₅₀ 0.94 mg/mL) than those of substituted dihomocholesta-trien-ol (2) and homocholesta-dien-diol (3) (IC₅₀ > 1.00 mg/mL). Structure-activity relationship studies demonstrated that bioactive potentials of the titled compounds were linearly related to their electronic factors along with optimum hydrophobic factors. In addition, molecular docking studies were performed in the active sites of COX-2 and their binding energies and docking scores were well correlated with in vitro anti-COX-2 potentials.

Binding of indomethacin methyl ester to cyclooxygenase-2. A computational study

Inhibitors selective towards the second isoform of prostaglandin synthase (cyclooxygenase, COX-2) are promising nonsteroidal anti-inflammatory drugs and antitumor medications. Methylation of the carboxylate group in the relatively nonselective COX inhibitor indomethacin confers significant COX-2 selectivity. Several other modifications converting indomethacin into a COX-2 selective inhibitor have been reported. Earlier experimental and computational studies on neutral indomethacin derivatives suggest that the methyl ester derivative likely binds to COX-2 with a similar binding mode as that observed for the parent indomethacin. However, docking studies followed by molecular dynamics simulations revealed two possible binding modes in COX-2 for indomethacin methyl ester, which differs from the experimental binding mode found for indomethacin. Both alternative binding modes might explain the observed COX-2 selectivity of indomethacin methyl ester. Graphical abstract Binding of indomethacin methyl ester to cyclooxygenase-2.

Magnetic field distribution modulation of intrathecal delivered ketorolac iron-oxide nanoparticle conjugates produce excellent analgesia for chronic inflammatory pain

Background

Nanoparticles have become one of the most promising among the potential materials used for biomedical applications. However, few researchers have focused on their effects on analgesia. Despite the fact that various nanoparticles have been evaluated for drug delivery and MRI imaging contrast enhancement in clinical settings, no reports have investigated the in vivo synergy of ketorolac iron-oxide nanoparticle conjugates to improve the analgesic effect.

Methods

Ketorolac conjugated magnetic iron oxide nanoparticles (Keto-SPIO) were synthesized via two-stage additions of protective agents and chemical co-precipitation. ICR mice were used to develop inflammatory pain models induced by Complete Freund’s adjuvant (CFA) injection in the hind paw. Different magnet field strengths and polarities were applied to the spinal cord after injecting Keto-SPIO into the theca space. Analgesia behavior was evaluated with the up-down method via von Frey microfilament measurement. Spinal cord tissues were harvested at the end analgesia time point upon induction of the inflammatory pain. The presence of the two cyclooxygenases (COX) in the spinal cord was examined via Western blotting to quantify the changes after intra-thecal Keto-SPIO administration.

Results

Intrathecal Keto-SPIO administration demonstrated a magnetic field-dependent analgesia effect in CFA pain model with a significant reduction in COX expression.

Conclusions

Our results indicated that intrathecal administration of the Keto-SPIO combined magnet field modulated delivery significantly promoted an analgesia effect with suppression of COX in the mice inflammatory pain model.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0375-9) contains supplementary material, which is available to authorized users.

Effect of acetylcholinesterase inhibitors donepezil and rivastigmine on the activity and expression of cyclooxygenases in a model of the inflammatory action of fluoride on macrophages obtained from THP-1 monocytes

Inflammation is an important factor in the development of many diseases of the central nervous system, including Alzheimer's disease and other types of dementia. ‪Given that acetylcholinesterase inhibitors are also currently believed to have anti-inflammatory properties, the purpose of this study was to investigate the effect of acetylcholinesterase inhibitors (rivastigmine, donepezil) on cyclooxygenase activity and expression using the proinflammatory action of fluoride (F^-) on cultured macrophages obtained from THP-1 monocytes. COX-1 and COX-2 activity was determined through measurement of the products of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) in cell culture supernatants. Expression of COX-1 and COX-2 proteins was examined immunocytochemically, and mRNA expression was determined by qRT PCR. ‪‪ Our study confirmed the inhibitory effects of donepezil and rivastigmine on the production of PGE2, TXB2, COX-1 and COX-2 mRNA and protein expression in macrophages. We also demonstrated that the pro-inflammatory effect of fluoride may be reduced by the use of both drugs. The additive effect of these drugs cannot be ruled out, and effects other than those observed in the use of one drug should also be taken into account.

Cisplatin increases the number of enterochromaffin cells containing substance P in rat intestine

We previously reported that cisplatin potentiated ileal 5-hydroxytryptamine (5-HT) metabolism and caused pathological changes with an inflammatory response in the delayed phase (72 h) after administration to rats. In the present study, we further investigated the time-dependent effect of cisplatin on ileal 5-HT metabolism and the effects of combining cisplatin and anti-inflammatory drugs on ileal tryptophan hydroxylase expression and pica (the consumption of non-nutritive materials such as kaolin). Cyclooxygenase-2 (COX-2) expression was significantly increased at 24 h after cisplatin (5 mg/kg, intraperitoneal) administration. Cisplatin significantly increased ileal 5-HT content at 48 h after administration and the number of L-tryptophan hydroxylase-expressing cells (i.e., enterochromaffin cells) in the ileal mucosa within 24 h after administration. It also caused a significant increase in the number of substance P-expressing cells. Immunohistochemical double staining revealed that most of the enterochromaffin cells contained substance P. Neither daily treatment with dexamethasone (1 mg/kg, subcutaneous) nor meloxicam (3 mg/kg, subcutaneous), a selective COX-2 inhibitor, affected the cisplatin-induced increase in the number of enterochromaffin cells. Meloxicam had no effect on cisplatin-induced pica, although dexamethasone almost completely inhibited it. This study demonstrated that cisplatin administration induced COX-2 expression and increased the number of enterochromaffin cells in the acute phase (i.e., within 24 h). However, COX-2 expression in the ileum seems to have little direct effect on the mechanism of the induction of enterochromaffin cells and pica.

Anti-neuroinflammatory effects of Ginkgo biloba extract EGb761 in LPS-activated primary microglial cells

BACKGROUND

Neuroinflammation is a key factor of Alzheimer's disease (AD) and other neurodegenerative conditions. Microglia are the resident mononuclear immune cells of the central nervous system (CNS). They play an essential role in the maintenance of homeostasis and responses to neuroinflammation. Ginkgo biloba extract EGb 761 is one of the most commonly used natural medicines owing to its established efficacy and remarkable biological activities especially in respect to CNS diseases. However, only few studies have addressed the effects and mechanisms of Ginkgo biloba extract in microglia activation.

METHODS

We measured the production of pro-inflammatory mediators and cytokines by ELISA and analyzed gene expressions by qRT-PCR and Western Blot in LPS treated cultured primary rat microglia.

RESULTS

The Ginkgo biloba extract EGb 761 significantly inhibited the release of prostaglandin E₂ (PGE₂) and differentially regulated the levels of pro-inflammatory cytokines. The inhibition of LPS-induced PGE₂ release in primary microglia was partially dependent on reduced protein synthesis of mPGES-1 and the reduction in the activation of cytosolic phospholipase A2 (cPLA2) without altering COX-2 enzymatic activity, inhibitor of kappa B alpha (IkappaBalpha) degradation, and the activation of multiple mitogen activated protein kinases (MAPKs). Altogether, we showed that EGb 761 reduces neuro-inflammatory activation in primary microglial cells by targeting PGE₂ release and cytokines.

CONCLUSION

Ginkgo biloba extract EGb 761 displayed anti-neuroinflammatory activity in LPS-activated primary microglia cells. EGb 761 was able to reduce neuroinflammatory activation by targeting the COX/PGE₂ pathway. This effect might contribute to the established clinical cognitive efficacy in Alzheimer's disease, vascular and mixed dementia.

Cyclooxygenase and lipoxygenase gene expression in the inflammogenesis of breast cancer

We examined the expression of major inflammatory genes, cyclooxygenase-1 and 2 (COX1, COX2) and arachidonate 5-lipoxygenase (ALOX5) in 1090 tumor samples of invasive breast cancer from The Cancer Genome Atlas (TCGA). Mean cyclooxygenase expression (COX1 + COX2) ranked in the upper 99th percentile of all 20,531 genes and surprisingly, the mean expression of COX1 was more than tenfold higher than COX2. Highly significant correlations were observed between COX2 with eight tumor-promoting genes (EGR2, IL6, RGS2, B3GNT5, SGK1, SLC2A3, SFRP1 and ETS2) and between ALOX5 and ten tumor promoter genes (CD33, MYOF1, NLRP1, GAB3, CD4, IFR8, CYTH4, BTK, FGR, CD37). Expression of CYP19A1 (aromatase) was significantly correlated with COX2, but only in tumors positive for ER, PR and HER2. Tumor-promoting genes correlated with the expression of COX1, COX2, and ALOX5 are known to effectively increase mitogenesis, mutagenesis, angiogenesis, cell survival, immunosuppression and metastasis in the pathogenesis of breast cancer.

The phospholipase A2 pathway controls a synaptic cholesterol ester cycle and synapse damage

The cellular prion protein (PrP^C) acts as a scaffold protein that organises signalling complexes. In synaptosomes, the aggregation of PrP^C by amyloid-β (Aβ) oligomers attracts and activates cytoplasmic phospholipase A₂ (cPLA₂), leading to synapse degeneration. The signalling platform is dependent on cholesterol released from cholesterol esters by cholesterol ester hydrolases (CEHs). The activation of cPLA₂ requires cholesterol released from cholesterol esters by cholesterol ester hydrolases (CEHs), enzymes dependent upon platelet activating factor (PAF) released by activated cPLA₂ This demonstrates a positive feedback system in which activated cPLA₂ increased cholesterol concentrations, which in turn facilitated cPLA₂ activation. PAF was also required for the incorporation of the tyrosine kinase Fyn and cyclooxygenase (COX)-2 into Aβ-PrP^C-cPLA₂ complexes. As a failure to deactivate signalling complexes can lead to pathology, the mechanisms involved in their dispersal were studied. PAF facilitated the incorporation of acyl-coenzyme A:cholesterol acyltransferase (ACAT)-1 into Aβ-PrP^C-cPLA₂-COX-2-Fyn complexes. The esterification of cholesterol reduced cholesterol concentrations, causing dispersal of Aβ-PrP^C-cPLA₂-COX-2-Fyn complexes and the cessation of signalling. This study identifies PAF as a key mediator regulating the cholesterol ester cycle, activation of cPLA₂ and COX-2 within synapses, and synapse damage.

The impact of night-shift work on platelet function in healthy medical staff

Objectives:

Rotating shift work has been reported to increase the risk of cardiovascular diseases. Vascular endothelial dysfunction and platelet activation are among the leading causes of thrombus formation in patients with myocardial infarction or stroke. Endothelial function has been shown to be impaired immediately after night-shift work; however, it is not known whether platelets are also activated. The aim of this study was to investigate the acute impact of night-shift work on platelet function.

Methods:

This observational study included 11 healthy medical staff members (seven women, median age 32 years). We examined each subject's platelet aggregation rates and the serum concentrations of eicosanoid mediators after night-shift work and on day-shift work without preceding night-shift work (baseline).

Results:

Platelet aggregation did not differ from baseline levels after night-shift work. However, serum cyclooxygenase (COX)-metabolized eicosanoid mediators, particularly thromboxane (Tx) B₂ (a stable metabolite of TxA₂ and the most important marker of platelet activation), were significantly higher after the night-shift than at baseline (median 65.3 vs 180.4 ng/ml).

Conclusions:

Although platelet aggregation did not increase, there was an increase in serum COX-metabolized eicosanoid mediators such as TxB₂ in healthy medical staff after night-shift work. This platelet hypersensitivity may be one of the mechanisms underlying the significant association between night-shift work and adverse cardiovascular outcomes.

Effects of phenidone (DuCLOX-2/5 inhibitor) against N-methyl-N-nitrosourea induced mammary gland carcinoma in albino rats

The present study was designed to evaluate the effects of phenidone (Dual inhibitor of COX-2 and 5-LOX, DuCLOX-2/5 inhibitor) on various aspects of cancer chemoprevention. Treatment with the phenidone was inquested to validate the implications of dual inhibition of arachidonic acid (AA) metabolism against MNU induced mammary gland carcinogenesis. MNU treated rat showed altered hemodynamic profile, distorted cellular architecture, upregulated inflammatory enzyme markers (COX, LOX, Nitric oxide and hydrogen sulfide) and distorted oxidative stress markers (thiobarbituric acid reactive substances, protein carbonyl, superoxide dismutase, catalase and glutathione). Phenidone treatment regulated histological architecture in the experimental animals similar to control. The treatment with phenidone favorably regulated the levels of inflammatory markers, and oxidative stress markers against toxic treatment. Our findings emphasize the potential role of phenidone in suppression of mammary gland carcinoma against the deleterious effects of MNU.