Constitutive COX-1 Research Articles

Dual COX-2/TNF-α Inhibitors as Promising Anti-inflammatory and Cancer Chemopreventive Agents: A Review

: Cyclooxygenases (COX) play a pivotal role in inflammation and are responsible for the production of prostaglandins (PGs). Two types of COXs have been identified as key biological targets for drug design: Constitutive COX-1 and inducible COX-2. Nonsteroidal anti-inflammatory drugs (NSAIDs) target COX-1, while selective COX-2 inhibitors are designed for COX-2. These COX isoforms are involved in multiple physiological and pathological pathways throughout the body. Overproduction of tumor necrosis factor-alpha (TNF-α) plays a role in COX-2's inflammatory activity. Tumor necrosis factor-alpha can contribute to cardiac fibrosis, heart failure, and various cancers by upregulating the COX-2/PGE2 axis. Therefore, suppressing COX activity has emerged as a potentially effective treatment for chronic inflammatory disorders and cancer. This review explores the mechanisms of TNF-α-induced COX-2/PGE2 expression, a significant pathophysiological feature of cancer development. Furthermore, we summarize chemical compounds with dual COX-2/TNF-α inhibitory actions, providing an overview of their structure-activity relationship. These insights may contribute to the development of new generations of dual-acting COX-2/TNF-α inhibitors with enhanced efficacy.

Inhibition of rat locus coeruleus neurons by prostaglandin E2 EP3 receptors: pharmacological characterization ex vivo.

Prostaglandin E2 (PGE2) is an inflammatory mediator synthesized by the brain constitutive cyclooxygenase enzyme. PGE2 binds to G protein-coupled EP1-4 receptors (EP1 to Gq, EP2,4 to Gs, and EP3 to Gi/o). EP2, EP3 and EP4 receptors are expressed in the locus coeruleus (LC), the main noradrenergic nucleus in the brain. EP3 receptors have been explored in the central nervous system, although its role regulating the locus coeruleus neuron activity has not been pharmacologically defined. Our aim was to characterize the function of EP3 receptors in neurons of the LC. Thus, we studied the effect of EP3 receptor agonists on the firing activity of LC cells in rat brain slices by single-unit extracellular electrophysiological techniques. The EP3 receptor agonist sulprostone (0.15nM-1.28µM), PGE2 (0.31nM-10.2µM) and the PGE1 analogue misoprostol (0.31nM-2.56µM) inhibited the firing rate of LC neurons in a concentration-dependent manner (EC50 = 15nM, 110nM, and 51nM, respectively). The EP3 receptor antagonist L-798,106 (3-10µM), but not the EP2 (PF-04418948, 3-10µM) or EP4 (L-161,982, 3-10µM) receptor antagonists, caused rightward shifts in the concentration-effect curves for the EP3 receptor agonists. Sulprostone-induced effect was attenuated by the Gi/o protein blocker pertussis toxin (pertussis toxin, 500ngml-1) and the inhibitors of inwardly rectifying potassium channels (GIRK) BaCl2 (300µM) and SCH-23390 (15µM). In conclusion, LC neuron firing activity is regulated by EP3 receptors, presumably by an inhibitory Gi/o protein- and GIRK-mediated mechanism.

Inactivation of TRPM7 Kinase Targets AKT Signaling and Cyclooxygenase-2 Expression in Human CML Cells.

Cyclooxygenase-2 (COX-2) is a key regulator of inflammation. High constitutive COX-2 expression enhances survival and proliferation of cancer cells, and adversely impacts antitumor immunity. The expression of COX-2 is modulated by various signaling pathways. Recently, we identified the melastatin-like transient-receptor-potential-7 (TRPM7) channel-kinase as modulator of immune homeostasis. TRPM7 protein is essential for leukocyte proliferation and differentiation, and upregulated in several cancers. It comprises of a cation channel and an atypical α-kinase, linked to inflammatory cell signals and associated with hallmarks of tumor progression. A role in leukemia has not been established, and signaling pathways are yet to be deciphered. We show that inhibiting TRPM7 channel-kinase in chronic myeloid leukemia (CML) cells results in reduced constitutive COX-2 expression. By utilizing a CML-derived cell line, HAP1, harboring CRISPR/Cas9-mediated TRPM7 knockout, or a point mutation inactivating TRPM7 kinase, we could link this to reduced activation of AKT serine/threonine kinase and mothers against decapentaplegic homolog 2 (SMAD2). We identified AKT as a direct in vitro substrate of TRPM7 kinase. Pharmacologic blockade of TRPM7 in wildtype HAP1 cells confirmed the effect on COX-2 via altered AKT signaling. Addition of an AKT activator on TRPM7 kinase-dead cells reconstituted the wildtype phenotype. Inhibition of TRPM7 resulted in reduced phosphorylation of AKT and diminished COX-2 expression in peripheral blood mononuclear cells derived from CML patients, and reduced proliferation in patient-derived CD34+ cells. These results highlight a role of TRPM7 kinase in AKT-driven COX-2 expression and suggest a beneficial potential of TRPM7 blockade in COX-2-related inflammation and malignancy.

Macroalgae Specialized Metabolites: Evidence for Their Anti-Inflammatory Health Benefits.

Inflammation is an organism's response to chemical or physical injury. It is split into acute and chronic inflammation and is the last, most significant cause of death worldwide. Nowadays, according to the World Health Organization (WHO), the greatest threat to human health is chronic disease. Worldwide, three out of five people die from chronic inflammatory diseases such as stroke, chronic respiratory diseases, heart disorders, and cancer. Nowadays, anti-inflammatory drugs (steroidal and non-steroidal, enzyme inhibitors that are essential in the inflammatory process, and receptor antagonists, among others) have been considered as promising treatments to be explored. However, there remains a significant proportion of patients who show poor or incomplete responses to these treatments or experience associated severe side effects. Seaweeds represent a valuable resource of bioactive compounds associated with anti-inflammatory effects and offer great potential for the development of new anti-inflammatory drugs. This review presents an overview of specialized metabolites isolated from seaweeds with in situ and in vivo anti-inflammatory properties. Phlorotannins, carotenoids, sterols, alkaloids, and polyunsaturated fatty acids present significant anti-inflammatory effects given that some of them are involved directly or indirectly in several inflammatory pathways. The majority of the isolated compounds inhibit the pro-inflammatory mediators/cytokines. Studies have suggested an excellent selectivity of chromene nucleus towards inducible pro-inflammatory COX-2 than its constitutive isoform COX-1. Additional research is needed to understand the mechanisms of action of seaweed's compounds in inflammation, given the production of sustainable and healthier anti-inflammatory agents.

Anti-inflammatory drugs with therapeutic effects and drug regulators

For prostaglandin production, the enzyme cyclooxygenase (COX) is required. The two COX isoforms are constitutive COX-1 (which is responsible for physiological functions) and inducible COX-2 (involved in inflammation). COX inhibition explains both the medicinal (inhibition of COX-2) and negative effects (inhibition of COX-1) effects of non-steroidal anti-inflammatory medicines (NSAIDs). Nonsteroidal anti-inflammatory medicines (NSAIDs) act by blocking the enzyme cyclooxygenase (COX), which produces prostaglandins (PGs). To a greater or lesser extent, they share similar side effects, such as stomach and renal toxicity. According to a recent study, there are at least two COX isoenzymes. COX-1 is a naturally occurring enzyme that creates prostaglandins (PGs), which protect the stomach and kidneys. Aspirin's well-known anti-cancer impact could also be related to its influence on COX-2, which is expressed in this condition. As a result, selective COX-2 inhibitors may have new therapeutic potential as anticancer drugs, as well as in preventing premature labor and maybe reducing the progression of Alzheimer's disease.

Progress in PET Imaging of Neuroinflammation Targeting COX-2 Enzyme.

Neuroinflammation and cyclooxygenase-2 (COX-2) upregulation are associated with the pathogenesis of degenerative brain diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), epilepsy, and a response to traumatic brain injury (TBI) or stroke. COX-2 is also induced in acute pain, depression, schizophrenia, various cancers, arthritis and in acute allograft rejection. Positron emission tomography (PET) imaging allows for the direct measurement of in vivo COX-2 upregulation and thereby enables disease staging, therapy evaluation and aid quantifying target occupancy of novel nonsteroidal anti-inflammatory drugs or NSAIDs. Thus far, no clinically useful radioligand is established for monitoring COX-2 induction in brain diseases due to the delay in identifying qualified COX-2-selective inhibitors entering the brain. This review examines radiolabeled COX-2 inhibitors reported in the past decade and identifies the most promising radioligands for development as clinically useful PET radioligands. Among the radioligands reported so far, the three tracers that show potential for clinical translation are, [11CTMI], [11C]MC1 and [18F]MTP. These radioligands demonstrated BBB permeablity and in vivo binding to constitutive COX-2 in the brain or induced COX-2 during neuroinflammation.

Anti-inflammatory β-sitosterols from the Asiatic loop-root mangrove Rhizophora mucronata attenuate 5-lipoxygenase and cyclooxygenase-2 enzymes

Four biogenic β-sitosterol analogues were identified from methanolic extract of the leaves of loop-root mangrove Rhizophora mucronata. These were characterized as 4, 14, 23-trimethyl-3β-sitosterol (1), 7-ethyl-3β-sitosterol (2), sitosteryl-3β-(33E)-pent-33-enoate (3) and 12α-hydroxy-3β-sitosterol (4) based on comprehensive spectroscopic techniques. Anti-inflammatory activities of β-sitosterol 4 against pro-inflammatory enzymes 5-lipoxygenase and cyclooxygenase-2 were found to be significantly higher (IC50 1.85 and 1.92 mM, respectively) compared to those demonstrated by compounds of 1–3 (p < 0.05). These β-sitosterol analogues disclosed superior selectivity indices (1.43–2.07) with regard to inducible cyclooxygenase-2 than its constitutive isoform cyclooxygenase-1, when compared to the standard, ibuprofen (0.44). Antioxidant properties of 12α-hydroxy-β-sitosterol (4) were found to be significantly greater (IC50 1.43–1.67 mM) than those of other sitosterol analogues. Structure-activity correlation analyses put forward that the bioactive potencies of the titled β-sitosterols were positively correlated to their electronic parameters. Molecular docking simulations were carried out in the active sites of 5-lipoxygenase/cyclooxygenase-2, and the docking scores and binding energies of the studied β-sitosterol analogues were positively correlated with their attenuation properties against 5-lipoxygenase and cyclooxygenase-2.

Anti-inflammatory pregnane-type steroid derivatives clathroids A-B from the marine Microcionidae sponge Clathria (Thalysias) vulpina: Prospective duel inhibitors of pro-inflammatory cyclooxygenase-2 and 5-lipoxygenase

Two pregnane-type of steroid derivatives characterized as 5α-pregna-3β-methyl pent-3-enoate-12β, 16β diol-20-one (clathroid A) and 12β,15β- dihydroxypregna-4,6-diene-3,20-dione (clathroid B) were purified from the crude extract of the marine sponge, Clathria (Thalysias) vulpina (family Microcionidae) by extensive chromatographic fractionation. Spectroscopic methods including nuclear magnetic resonance spectroscopy were employed to characterize the purified clathroids A-B. The studied compounds exhibited duel inhibitory potentials against pro-inflammatory cyclooxygenase-2 and 5-lipoxygenase (median inhibitory concentration, IC50 < 1 mM), whereas the attenuation property of clathroid A against 5-lipoxygenase (IC50 0.85 mM) was greater than the standard anti-inflammatory ibuprofen (IC50 4.51 mM, p < 0.05). Greater selectivity index (anti cyclooxygense-2/anti cyclooxygense-1) of the studied clathroids (>1) than ibuprofen (0.43) attributed the greater selective attenuation properties towards pro-inflammatory inducible cyclooxygenase-2 than its constitutive isoenzyme cyclooxygenase-1. The antioxidant potentials of clathroid A against 2, 2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (IC50 0.80 mM) and diphenyl-1-picrylhydrazyl (IC50 0.83 mM) free radicals were greater than those of clathroid B (IC50 0.86–0.96 mM). Structure–activity analyses showed that the bioactivities of the clathroids were directly related to their electronic parameters coupled with permissible hydrophobic properties. Clathroid A exhibited grater electronic parameter (topological polar surface area tPSA, 83.83) than clathroid B (74.60) and ibuprofen (37.30), which were found to be in agreement with the prospective anti-inflammatory profile of clathroid A. Clathroid A exhibited higher number of hydrogen bonding interactions with 5-lipoxygenase active site and lesser docking values, such as docking score (DS −12.90 kcal mol−1) and inhibition constant (Ki 1.11 nM) than those recorded by clathroid B (DS −10.49 kcal mol−1; Ki 13.88 nM). The molecular binding properties of clathroid A with 5-lipoxidase inferred that its docking score/ binding energy were positively correlated with their in vitro bioactivie potentilas. A putative biosynthetic pathway of the studied clathroids was proposed from a pregnenolone precursor. The present study recognized the potential of clathroid A isolated from C. (Thalysias) vulpina as prospective anti-inflammatory lead that could find its use in medicinal applications.

Overview on the Discovery and Development of Anti-Inflammatory Drugs: Should the Focus Be on Synthesis or Degradation of PGE2?

Inflammation is a protective response that develops against tissue injury and infection. Chronic inflammation, on the other hand, is the key player in the pathogenesis of many inflammatory disorders including cancer. The cytokine storm, an inflammatory response flaring out of control, is mostly responsible for the mortality in COVID-19 patients. Anti-inflammatory drugs inhibit cyclooxygenases (COX), which are involved in the biosynthesis of prostaglandins that promote inflammation. The conventional non-steroidal anti-inflammatory drugs (NSAIDs) are associated with gastric and renal side-effects, as they inhibit both the constitutive COX-1 and the inducible COX-2. The majority of selective COX-2 inhibitors (COXIBs) are without gastric side-effects but are associated with cardiac side-effects on long-term use. The search for anti-inflammatory drugs without side-effects, therefore, has become a dream and ongoing effort of the Pharma companies. As PGE2 is the key mediator of inflammatory disorders, coming up with a strategy to reduce the levels of PGE2 alone without affecting other metabolites may form a better choice for the development of next generation anti-inflammatory drugs. In this direction the options being explored are on synthesis of PGE2-mPGES-1; PGE2 degradation through a specific PG dehydrogenase, 15-PGDH, and by blocking its activity mediated through a specific PGE receptor, EP4. As leukotrienes formed via the 5-lipoxygenase (5-LOX) pathway also play an important role in the mediation of inflammation, efforts are also being made to target both COX and LOX pathways. This review focuses on addressing the following three points: 1) How NSAIDs and COXIBs are associated with gastric, renal and cardiac side-effects; 2) Should the focus be on the targets upstream or downstream of PGE2; and 3) the status of alternative targets being explored for the discovery and development of anti-inflammatory drugs without side-effects.

Radiosynthesis and evaluation of [18F]FMTP, a COX-2 PET ligand.

The upregulation of cyclooxygenase-2 (COX-2) is involved in neuroinflammation associated with many neurological diseases as well as cancers of the brain. Outside the brain, inflammation and COX-2 induction contribute to the pathogenesis of pain, arthritis, acute allograft rejection, and in response to infections, tumors, autoimmune disorders, and injuries. Herein, we report the radiochemical synthesis and evaluation of [18F]6-fluoro-2-(4-(methylsulfonyl)phenyl)-N-(thiophen-2-ylmethyl)pyrimidin-4-amine ([18F]FMTP), a high-affinity COX-2 inhibitor, by cell uptake and PET imaging studies. The radiochemical synthesis of [18F]FMTP was optimized using chlorine to fluorine displacement method, by reacting [18F]fluoride/K222/K2CO3 with the precursor molecule. Cellular uptake studies of [18F]FMTP was performed in COX-2 positive BxPC3 and COX-2 negative PANC-1 cell lines with unlabeled FMTP as well as celecoxib to define specific binding agents. Dynamic microPET image acquisitionwas performed in anesthetized nude mice (n = 3), lipopolysaccharide (LPS) induced neuroinflammation mice (n = 4), and phosphate-buffered saline (PBS) administered control mice (n = 4) using a Trifoil microPET/CT for a scan period of 60min. A twofold higher binding of [18F]FMTP was found in COX-2 positive BxPC3 cells compared with COX-2 negative PANC-1 cells. The radioligand did not show specific binding to COX-2 negative PANC-1 cells. MicroPET imaging in wild-type mice indicated blood-brain barrier (BBB) penetration and fast washout of [18F]FMTP in the brain, likely due to the low constitutive COX-2 expression in the normal brain. In contrast, a ~ twofold higher uptake of the radioligand was found in LPS-induced mice brain than PBS treated control mice. Specific binding to COX-2 in BxPC3 cell lines, BBB permeability, and increased brain uptake in neuroinflammation mice qualifies [18F]FMTP as a potential PET tracer for studying inflammation.

Tu1542 INCREASED PREVALENCE OF BARRETT’S ESOPHAGUS IN PATIENTS WITH DUODENAL ADENOMA

Duodenal adenomas are relatively common in patients with familial adenomatous polyposis (FAP) but sporadic duodenal adenomas are rare. Cyclooxygenase 2 (COX-2) is an important regulatory protein identified in the upper gastrointestinal adenoma-carcinoma sequence. Some studies have shown constitutive COX-2 expression in normal duodenum and esophagus and higher levels in dysplastic esophageal tissue and Barrett’s esophagus (BE). However, the prevalence of BE in patients with duodenal adenomas has not been described. A retrospective cross-sectional study was performed using our electronic endoscopy and pathology database. Study subjects included all patients with duodenal adenoma at our tertiary care academic medical center from Sept 2009 to Sept 2018. Data regarding patient demographics, comorbid conditions and medication use was noted. We also collected information regarding endoscopic and histological findings. A total of 333 patients with duodenal adenoma were included in the study. The average age was 71.6 years and 50.1% were females. A total of 13% of patients had FAP. Barrett’s esophagus was identified in 32 patients (9.6%). There was no difference in patient characteristics amongst patients with duodenal adenoma who had BE as compared to those who did not [Table 1]. As compared to the general population, 43.7% of duodenal adenoma patients who had BE were female. In patients with duodenal adenoma, patients on proton pump inhibitor (PPI) therapy have higher Barrett’s esophagus 15.2% vs 3.2% (p value 0.001). On a multivariate analysis patients with duodenal adenoma not using PPI have significantly lower Barrett’s esophagus [OR=0.14, ( 95% CI: 0.04- 0.52, p-value: 0.003] Despite our study limitations of referral bias and a single center experience, our findings demonstrate that 1 in 10 patients with duodenal adenoma have concomitant Barrett’s esophagus. The prevalence of Barrett’s esophagus in patients with duodenal adenoma is higher than in the general population. Previously some reports have shown changes in expression of some cell regularity proteins such as COX-2 in patients with duodenal adenomas, and COX-2 has also been reported to be increased in BE. Further studies are needed evaluating molecular characteristics in these patients to see if this finding has any clinical significance.

NONSTEROIDAL ANTI-INFLAMMATORY DRUGS AS THERAPEUTIC ALLIES OF THE GUT MICROBIOME ON CHRONIC INFLAMMATION

Our gut harbours around 1014 bacteria of more than 1000 species, accounting for approximately 2 kg of biomass. The gut microbiome plays several vital functions in processes such as the development of the immune system, food digestion and protection against pathogens. For these functions to be beneficial for both host and microbiome, interactions are tightly regulated. Gut and immune cells continuously interact to distinguish among commensal microbiota, harmless foodstuff, and pathogens. A fine balance between inflammatory and anti-inflammatory state is fundamental to protect intestinal homeostasis. Nonsteroidal anti-inflammatories (NSAIDs) are a class of drugs used for management of pain and inflammation. These compounds have heterologous structures but similar therapeutic activities. The target of all NSAIDs are the isoforms of cyclooxygenase enzymes (COX): the primarily constitutive form COX-1, and the inducible from COX-2. Both isoforms catalyse the conversion of arachidonic acid to PGH2, the immediate substrate for specific prostaglandin and thromboxane synthesis. The gut microbiota plays a role in drug metabolism, resulting in altered bioavailability of these compounds. Additionally, complex host-microbiome interactions lead to modified xenobiotic metabolism and altered expression of genes involved in drug metabolism. These effects can be at gut tissue-level, or distant, including in the liver. Besides the gut microbiome influencing drug metabolism, drugs also impact the microbial communities in the gut. As different drugs exert selective pressures on the gut microbiome, understanding this bidirectional relationship is crucial for developing effective therapies for managing chronic inflammation.

Druggable Prostanoid Pathway.

Prostanoids (prostaglandins, prostacyclin and thromboxane) belong to the oxylipin family of biologically active lipids generated from arachidonic acid (AA). Protanoids control numerous physiological and pathological processes. Cyclooxygenase (COX) is a rate-limiting enzyme involved in the conversion of AA into prostanoids. There are two COX isozymes: the constitutive COX-1 and the inducible COX-2. COX-1 and COX-2 have similar structures, catalytic activities, and subcellular localizations but differ in patterns of expression and biological functions. Non-selective COX-1/2 or traditional, non-steroidal anti-inflammatory drugs (tNSAIDs) target both COX isoforms and are widely used to relieve pain, fever and inflammation. However, the use of NSAIDs is associated with various side effects, particularly in the gastrointestinal tract. NSAIDs selective for COX-2 inhibition (coxibs) were purposefully designed to spare gastrointestinal toxicity, but predisposed patients to increased cardiovascular risks. These health complications from NSAIDs prompted interest in the downstream effectors of the COX enzymes as novel drug targets. This chapter describes various safety issues with tNSAIDs and coxibs, and discusses the current development of novel classes of drugs targeting the prostanoid pathway, including nitrogen oxide- and hydrogen sulfide-releasing NSAIDs, inhibitors of prostanoid synthases, dual inhibitors, and prostanoid receptor agonists and antagonists.

Cyclooxygenase-2 Inhibitors as a Therapeutic Target in Inflammatory Diseases.

Inflammation plays a crucial role in the development of many complex diseases and disorders including autoimmune diseases, metabolic syndrome, neurodegenerative diseases, and cardiovascular pathologies. Prostaglandins play a regulatory role in inflammation. Cyclooxygenases are the main mediators of inflammation by catalyzing the initial step of arachidonic acid metabolism and prostaglandin synthesis. The differential expression of the constitutive isoform COX-1 and the inducible isoform COX-2, and the finding that COX-1 is the major form expressed in the gastrointestinal tract, lead to the search for COX-2-selective inhibitors as anti-inflammatory agents that might diminish the gastrointestinal side effects of traditional non-steroidal anti-inflammatory drugs (NSAIDs). COX-2 isoform is expressed predominantly in inflammatory cells and decidedly upregulated in chronic and acute inflammations, becoming a critical target for many pharmacological inhibitors. COX-2 selective inhibitors happen to show equivalent efficacy with that of conventional NSAIDs, but they have reduced gastrointestinal side effects. This review would elucidate the most recent findings on selective COX-2 inhibition and their relevance to human pathology, concretely in inflammatory pathologies characterized by a prolonged pro-inflammatory status, including autoimmune diseases, metabolic syndrome, obesity, atherosclerosis, neurodegenerative diseases, chronic obstructive pulmonary disease, arthritis, chronic inflammatory bowel disease and cardiovascular pathologies.

COX2 is induced in the ovarian epithelium during ovulatory wound repair and promotes cell survival†.

The ovarian surface epithelium (OSE) is a monolayer of cells surrounding the ovary that is ruptured during ovulation. After ovulation, the wound is repaired, however, this process is poorly understood. In epithelial tissues, wound repair is mediated by an epithelial-to-mesenchymal transition (EMT). Transforming Growth Factor Beta-1 (TGFβ1) is a cytokine commonly known to induce an EMT and is present throughout the ovarian microenvironment. We, therefore, hypothesized that TGFβ1 induces an EMT in OSE cells and activates signaling pathways important for wound repair. Treating primary cultures of mouse OSE cells with TGFβ1 induced an EMT mediated by TGFβRI signaling. The transcription factor Snail was the only EMT-associated transcription factor increased by TGFβ1 and, when overexpressed, was shown to increase OSE cell migration. A polymerase chain reaction array of TGFβ signaling targets determined Cyclooxygenase-2 (Cox2) to be most highly induced by TGFβ1. Constitutive Cox2 expression modestly increased migration and robustly enhanced cell survival, under stress conditions similar to those observed during wound repair. The increase in Snail and Cox2 expression with TGFβ1 was reproduced in human OSE cultures, suggesting these responses are conserved between mouse and human. Finally, the induction of Cox2 expression in OSE cells during ovulatory wound repair was shown in vivo, suggesting TGFβ1 increases Cox2 to promote wound repair by enhancing cell survival. These data support that TGFβ1 promotes ovulatory wound repair by induction of an EMT and activation of a COX2-mediated pro-survival pathway. Understanding ovulatory wound repair may give insight into why ovulation is the primary non-hereditary risk factor for ovarian cancer.

First report of spiro-compounds from marine macroalga Gracilaria salicornia: prospective natural anti-inflammatory agents attenuate 5-lipoxygenase and cyclooxygenase-2

The inflammation pathology is an orchestrated biological process and the dual inhibition of pro-inflammatory enzymes 5-lipoxygenase and cyclooxygenase-2 has been found to be an effective approach against inflammation. This study involves the characterisation of two previously undescribed spiro[5.5]undecanes, 3-(hydroxymethyl)-7-(methoxymethyl)-3,11-dimethyl-9-oxospiro[5.5]undec-4-en-10-methylbutanoate (1) and 4-ethoxy-11,11-dimethyl-7-methylene-8-(propionyloxy)spiro[5.5]undec-2-en-104,106-dihydroxytetrahydro-2H-pyran-10-carboxylate (2) with potential anti-inflammatory properties, from seaweed Gracilaria salicornia by extensive-spectroscopic-experiments. These metabolites recorded prospective bioactivities against 5-lipoxygenase (IC50 < 2.80 mM), whereas their selectivity indices were significantly greater (∼1) than ibuprofen (0.89) (p < 0.05), which attributed selective anti-inflammatory potencies of the studied spiro[5.5]undecane derivatives against inducible cyclooxygenase-2 than constitutive cyclooxygenase-1. Radical scavenging potential of spiro[5.5]undec-2-en-104,106-dihydroxytetrahydro-2H-pyran-10-carboxylate analogue (2) against oxidants, 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis-3 ethylbenzothiozoline-6-sulfonic acid were found to be greater (IC50 < 1.25 mM) than commercial standard, α-tocopherol (IC50 1.42–1.79 mM). The greater hydrogen-bonding interactions and binding affinity of 2 (−10.13 kcal/mol) with 5-LOX appropriately corroborated its prospective anti-inflammatory activity.

Cyclooxygenase-2 is acutely induced by CCAAT/enhancer-binding protein β to produce prostaglandin E 2 and F 2α following gonadotropin stimulation in Leydig cells.

Cyclooxygenase 2 (COX-2) is an inducible rate-limiting enzyme for prostanoid production. Because COX-2 represents one of the inducible genes in mouse mesenchymal stem cells upon differentiation into Leydig cells, we investigated COX-2 expression and production of prostaglandin (PG) in Leydig cells. Although COX-2 was undetectable in mouse testis, it was transiently induced in Leydig cells by human chorionic gonadotropin (hCG) administration. Consistent with the finding that Leydig cells expressed aldo-keto reductase 1B7 (PGF synthase) and PGE synthase 2, induction of COX-2 by hCG caused a marked increase in testicular PGF 2α and PGE 2 levels. Using mouse Leydig cell tumor-derived MA-10 cells as a model, it was indicated by reporter assays and electron mobility shift assays that transcription of the COX-2 gene was activated by CCAAT/enhancer-binding protein β (C/EBPβ) with cAMP-stimulation. C/EBPβ expression was induced by cAMP-stimulation, whereas expression of C/EBP homolog protein (CHOP) was robustly downregulated. Transfection of CHOP expression plasmid inhibited cAMP-induced COX-2 promoter activity. In addition, CHOP reduced constitutive COX-2 expression in other mouse Leydig cell tumor-derived TM3 cells. These results indicate that COX-2 is induced in Leydig cells by activation of C/EBPβ via reduction of CHOP expression upon gonadotropin-stimulation to produce PGF 2α and PGE 2 .

Cyclooxygenase-2 Selectively Controls Renal Blood Flow Through a Novel PPARβ/δ-Dependent Vasodilator Pathway.

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in inflammation and cancer targeted by nonsteroidal anti-inflammatory drugs. COX-2 is also expressed constitutively in discreet locations where its inhibition drives gastrointestinal and cardiovascular/renal side effects. Constitutive COX-2 expression in the kidney regulates renal function and blood flow; however, the global relevance of the kidney versus other tissues to COX-2-dependent blood flow regulation is not known. Here, we used a microsphere deposition technique and pharmacological COX-2 inhibition to map the contribution of COX-2 to regional blood flow in mice and compared this to COX-2 expression patterns using luciferase reporter mice. Across all tissues studied, COX-2 inhibition altered blood flow predominantly in the kidney, with some effects also seen in the spleen, adipose, and testes. Of these sites, only the kidney displayed appreciable local COX-2 expression. As the main site where COX-2 regulates blood flow, we next analyzed the pathways involved in kidney vascular responses using a novel technique of video imaging small arteries in living tissue slices. We found that the protective effect of COX-2 on renal vascular function was associated with prostacyclin signaling through PPARβ/δ (peroxisome proliferator-activated receptor-β/δ). These data demonstrate the kidney as the principle site in the body where local COX-2 controls blood flow and identifies a previously unreported PPARβ/δ-mediated renal vasodilator pathway as the mechanism. These findings have direct relevance to the renal and cardiovascular side effects of drugs that inhibit COX-2, as well as the potential of the COX-2/prostacyclin/PPARβ/δ axis as a therapeutic target in renal disease.

Pharmacological potential of sulfated polygalactopyranosyl-fucopyranan from the brown seaweed Sargassum wightii

A sulfated polygalactopyranosyl-fucopyranan characterized as ∙∙∙∙ → 1)-α-Fucp-(2SO3−)-(3 → 1)-α-Fucp-(2SO3−)-(4 → 1)-β-Galp-(4 → 1)-β-Galp-(4 → ∙∙∙∙ was isolated from the brown seaweed Sargassum wightii and evaluated for pharmacological properties with reference to antioxidant, anti-inflammatory, antidiabetic, and antihypertensive activities using different in vitro models. The sulfated polygalactopyranosyl-fucopyranan displayed potential di(phenyl)-(2,4,6-trinitrophenyl) iminoazanium (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) radical scavenging, and Fe2+ ion chelating activities (IC90 ~ 1 mg mL−1). The studied polysaccharide displayed higher anti-inflammatory selectivity towards inducive pro-inflammatory enzyme cyclooxygenase-2 (COX-2, IC90 1.13 mg mL−1) than constitutive cyclooxygenase-1 (COX-1, IC90 > 1.20 mg mL−1) resulting in greater selectivity index (IC90 COX-2/COX-1, 0.93) than synthetic non-steroidal anti-inflammatory drug aspirin (0.88) and also showed potent lipoxygenase-5 inhibition (LOX-5, IC90 1.02 mg mL−1). The studied polysaccharide displayed significantly higher (P < 0.05) antidiabetic properties compared to the antidiabetic agents acarbose and diprotein-A in terms of α-amylase (IC90 0.93 mg mL−1), α-glucosidase (IC90 1.48 mg mL−1), and dipeptidyl peptidase-4 (IC90 0.11 mg mL−1) enzyme inhibition potentials. The sulfated polygalactopyranosyl-fucopyranan also displayed potential antihypertensive activity with reference to angiotensin-converting enzyme-I inhibitory activity (IC90 0.2 mg mL−1). Extensive spectroscopic experiments in conjugation with monosaccharide compositional analysis attributed (1 → 3)-linked α-fucopyranose units in the polygalactofucan chain with C-2 sulfation and C-4 substituents as O-acetyl/O-methyl/(1 → 4)-linked β-galactopyranose. The previously undescribed sulfated polygalactopyranosyl-fucopyranan could function as a potential pharmacophore lead against inflammation, type 2 diabetics, hypertension and utilization as natural antioxidant.

Effect of mofezolac-galactose distance in conjugates targeting cyclooxygenase (COX)-1 and CNS GLUT-1 carrier

Neuroinflammation is the earliest stage of several neurological and neurodegenerative diseases. In the case of neurodegenerative disorders, it takes place about 15–20 years before the appearance of specific neurodegenerative clinical symptoms. Constitutive microglial COX-1 is one of the pro-inflammatory players of the neuroinflammation. Novel compounds 3, 14 and 15 (Galmof0, Galmof5 and Galmof11, respectively) were projected, and their synthetic methodologies developed, by linking by an ester bond, directly or through a C5 or C11 unit linker the highly selective COX-1 inhibitor mofezolac (COXs selectivity index > 6000) to galactose in order to obtain substances capable to cross blood-brain barrier (BBB) and control the CNS inflammatory response. 3, 14 and 15 (Galmofs) were prepared in good to fair yields. Galmof0 (3) was found to be a selective COX-1 inhibitor (COX-1 IC50 = 0.27 μM and COX-2 IC50 = 3.1 μM, selectivity index = 11.5), chemically and metabolically stable, and capable to cross Caco-2 cell monolayer, resembling BBB, probing that its transport is GLUT-1-mediated. Furthermore, Galmof0 (3) powerfully inhibits PGE2 release higher than mofezolac (1) in LPS-stimulated mouse BV2 microglial cell line, a worldwide recognized neuroinflammation model. In addition, Fingerprints for Ligands and Proteins (FLAP) was used to explain the different binding interactions of Galmofs with the COX-1 active site.