Highly Selective Cyclooxygenase-1 Inhibitors P6 and Mofezolac Counteract Inflammatory State both In Vitro and In Vivo Models of Neuroinflammation

Exploring the Neuroprotective Potential of N-Methylpyridinium against LPS-Induced Neuroinflammation: Insights from Molecular Mechanisms

N-methylpyridinium (NMP) is produced through the pyrolysis of trigonelline during the coffee bean roasting process. Preliminary studies suggest that NMP may have health benefits, thanks to its antioxidant properties. Based on this background, the aim of this study was to evaluate whether NMP could have a protective effect against LPS-induced neuroinflammation in human glioblastoma cells (U87MG). With this aim, U87MG cells were pre-treated with NMP (0.5 μM) for 1 h and then exposed to LPS (1 μg/mL) for 24 h. Our findings show that NMP attenuates LPS-induced neuroinflammation by reducing the expression of pro-inflammatory cytokines, such as IL-1β, TNF-α and IL-6, through the inhibition of the NF-κB signaling pathway, which is critical in regulating inflammatory responses. NMP is able to suppress the activation of the NF-κB signaling pathway, suggesting its potential in preventing neuroinflammatory conditions. These outcomes support the notion that regular consumption of NMP, possibly through coffee consumption, may offer protection against neuroinflammatory states implicated in neurological disorders.

Dihydroartemisinin, a potential PTGS1 inhibitor, potentiated cisplatin-induced cell death in non-small cell lung cancer through activating ROS-mediated multiple signaling pathways

Dihydroartemisinin (DHA) exerts an anti-tumor effect in multiple cancers, however, the molecular mechanism of DHA and whether DHA facilitates the anti-tumor efficacy of cisplatin in non-small cell lung cancer (NSCLC) are unclear. Here, we found that DHA potentiated the anti-tumor effects of cisplatin in NSCLC cells by stimulating reactive oxygen species (ROS)-mediated endoplasmic reticulum (ER) stress, C-Jun-amino-terminal kinase (JNK) and p38 MAPK signaling pathways both in vitro and in vivo. Of note, we demonstrated for the first time that DHA inhibits prostaglandin G/H synthase 1 (PTGS1) expression, resulting in enhanced ROS production. Importantly, silencing PTGS1 sensitized DHA-induced cell death by increasing ROS production and activating ER-stress, JNK and p38 MAPK signaling pathways. In summary, our findings provided new experimental basis and therapeutic prospect for the combined therapy with DHA and cisplatin in some NSCLC patients.

Prednisolone Targets Claudins in Mouse Brain Blood Vessels

Endothelial cells in brain capillaries are crucial for the function of the blood-brain barrier (BBB), and members of the tight junction protein family of claudins are regarded to be primarily responsible for barrier properties. Thus, the analysis of bioactive substances that can affect the BBB's permeability is of great importance and may be useful for the development of new therapeutic strategies for brain pathologies. In our study, we tested the hypothesis that the application of the glucocorticoid prednisolone affects the murine blood-brain barrier in vivo. Isolated brain tissue of control and prednisolone-injected mice was examined by employing immunoblotting and confocal laser scanning immunofluorescence microscopy, and the physiological and behavioral effects were analyzed. The control tissue samples revealed the expression of barrier-forming tight junction proteins claudin-1, -3, and -5 and of the paracellular cation and water-channel-forming protein claudin-2. Prednisolone administration for 7 days at doses of 70 mg/kg caused physiological and behavioral effects and downregulated claudin-1 and -3 and the channel-forming claudin-2 without altering their localization in cerebral blood vessels. Changes in the expression of these claudins might have effects on the ionic and acid-base balance in brain tissue, suggesting the relevance of our findings for therapeutic options in disorders such as cerebral edema and psychiatric failure.

Effect of microbial fermentation on functional traits and volatiloma profile of pâté olive cake

In this study, the pâté olive cake (POC), a by-product of the olive oil industry, was subjected to fermentation in a bioreactor using three microbial strains, Lactiplantibacillus plantarum, Wickerhamomyces anomalus and Candida boidinii, previously isolated from fermented table olive brines. Chemical, microbiological and molecular analyses were carried out at the beginning and at the end of fermentation. The lowest pH value (4.09) was reached after 10 days in sample inoculated with C. boidinii. Microbiological analyses exhibited the dominance of yeasts throughout the whole process (from 5.5 to 7.80 Log10 CFU/g), as confirmed by PCR-DGGE analysis. The microbial cultures affected both phenolic and volatile organic compound profiles. Moreover, the POC samples treated with different microbial strains were investigated for biological assays. The sample fermented with W. anomalus showed the greatest diffusion speed of transepithelial transport through Caco-2 cell, the highest inhibitory activity towards the tested cyclooxygenases and the highest antioxidant activity.

Insights into the advances in therapeutic drugs for neuroinflammation-related diseases

Studies have shown that neurodegenerative diseases such as AD and PD are related to neuroinflammation. Neuroinflammation is a common inflammatory condition that can lead to a variety of dysfunction in the body. At present, it is no medications specifically approved to prevent or cure neuroinflammation, so even though many drugs can temporarily control the neurological symptoms of neuroinflammation, but no one can reverse the progress of neuroinflammation, let al.one completely cure neuroinflammation. Therefore, it is urgent to develop new drug development for neuroinflammation treatment. In this review, we highlight the therapeutic advancement in the field of neurodegenerative disorders, by focusing on the impact of neuroinflammation treatment has on these conditions, and the effective drugs for the treatment of neuroinflammation and neurodegenerative diseases and their latest research progress are reviewed according to the related signaling pathway, as well as the prospect of their clinical application is also discussed. The purpose of this review is to enable specialists to better understand the mechanisms underlying neuroinflammation and anti-inflammatory drugs, promote the development of therapeutic drugs for neuroinflammation and neurodegenerative diseases, and further provide therapeutic references for clinical neurologists.

m-Terphenylamines, Acting as Selective COX-1 Inhibitors, Block Microglia Inflammatory Response and Exert Neuroprotective Activity

Inhibition of cyclooxygenase-2 (COX-2) has been extensively studied as an approach to reduce proinflammatory markers in acute brain diseases, but the anti-neuroinflammatory role of cyclooxygenase-1 (COX-1) inhibition has been rather neglected. We report that m-terphenylamine derivatives are selective COX-1 inhibitors, able to block microglia inflammatory response and elicit a neuroprotective effect. These compounds were synthesized via a three-component reaction of chalcones, β-ketoesters, and primary amines, followed by hydrolysis/decarboxylation of the ester group. Together with their synthetic intermediates and some urea derivatives, they were studied as inhibitors of COX-1 and COX-2. The m-terphenylamine derivatives, which were selective COX-1 inhibitors, were also analyzed for their ability to block microglia inflammatory and oxidative response. Compound 3b presented an interesting anti-inflammatory and neuroprotective profile by reducing nitrite release, ROS overproduction, and cell death in organotypic hippocampal cultures subjected to LPS. We thus show that COX-1 inhibition is a promising approach to provide enhanced neuroprotection against acute inflammatory processes, which are crucial in the development of a plethora of acute neurodegenerative injuries.

Mechanism of ligusticum cycloprolactam against neuroinflammation based on network pharmacology and experimental verification

Ligustilide, a natural phthalide mainly derived from chuanxiong rhizomes and Angelica Sinensis roots, possesses anti-inflammatory activity, particularly in the context of the nervous system. However, its application is limited because of its unstable chemical properties. To overcome this limitation, ligusticum cycloprolactam (LIGc) was synthesized through structural modification of ligustilide. In this study, we combined network pharmacological methods with experimental verification to investigate the anti-neuroinflammatory effects and mechanisms of ligustilide and LIGc. Based on our network pharmacology analysis, we identified four key targets of ligustilide involved in exerting an anti-inflammatory effect, with the nuclear factor (NF)-κB signal pathway suggested as the main signalling pathway. To verify these results, we examined the expression of inflammatory cytokines and inflammation-related proteins, analysed the phosphorylation level of NF-κB, inhibitor of κBα (IκBα) and inhibitor of κB kinase α and β (IKKα+β), and evaluated the effect of BV2 cell-conditioned medium on HT22 cells in vitro. Our results, demonstrate for the first time that LIGc can downregulate the activation of the NF-κB signal pathway in BV2 cells induced by lipopolysaccharide, suppress the production of inflammatory cytokines and reduce nerve injury in HT22 cells mediated by BV2 cells. These findings suggest that LIGc inhibits the neuroinflammatory response mediated by BV2 cells, providing strong scientific support for the development of anti-inflammatory drugs based on natural ligustilide or its derivatives. However, there are some limitations to our current study. In the future, further experiments using in vivo models may provide additional evidence to support our findings.

SC-560 and mofezolac isosteres as new potent COX-1 selective inhibitors with antiplatelet effect

Selective cyclooxygenase (COX)-1 inhibitors can be employed as potential cardioprotective drugs. Moreover, COX-1 plays a key role in inflammatory processes and its activity is associated with some types of cancer. In this work, we designed and synthesized a set of compounds that structurally mimic the selective COX-1 inhibitors, SC-560 and mofezolac, the central cores of which were replaced either with triazole or benzene rings. The advantage of this approach is a relatively simple synthesis in comparison with the syntheses of parent compounds. The newly synthesized compounds exhibited remarkable activity and selectivity toward COX-1 in the enzymatic in vitro assay. The most potent compound, 10a (IC50  = 3 nM for COX-1 and 850 nM for COX-2), was as active as SC-560 (IC50  = 2.4 nM for COX-1 and 470 nM for COX-2) toward COX-1 and it was even more selective. The in vitro COX-1 enzymatic activity was further confirmed in the cell-based whole-blood antiplatelet assay, where three out of four selected compounds (10a,c,d, and 3b) exerted outstanding IC50 values in the nanomolar range (9-252 nM). Moreover, docking simulations were performed to reveal key interactions within the COX-1 binding pocket. Furthermore, the toxicity of the selected compounds was tested using the normal human kidney HK-2 cell line.

Identification of Novel Cyclooxygenase-1 Selective Inhibitors of Thiadiazole-Based Scaffold as Potent Anti-Inflammatory Agents with Safety Gastric and Cytotoxic Profile

Major obstacles faced by the use of nonsteroidal anti-inflammatory drugs (NSAID) are their gastrointestinal toxicity induced by non-selective inhibition of both cyclooxygenases (COX) 1 and 2 and their cardiotoxicity associated with a certain class of COX-2 selective inhibitors. Recent studies have demonstrated that selective COX-1 and COX-2 inhibition generates compounds with no gastric damage. The aim of the current study is to develop novel anti-inflammatory agents with a better gastric profile. In our previous paper, we investigated the anti-inflammatory activity of 4-methylthiazole-based thiazolidinones. Thus, based on these observations, herein we report the evaluation of anti-inflammatory activity, drug action, ulcerogenicity and cytotoxicity of a series of 5-adamantylthiadiazole-based thiazolidinone derivatives. The in vivo anti-inflammatory activity revealed that the compounds possessed moderate to excellent anti-inflammatory activity. Four compounds 3, 4, 10 and 11 showed highest potency (62.0, 66.7, 55.8 and 60.0%, respectively), which was higher than the control drug indomethacin (47.0%). To determine their possible mode of action, the enzymatic assay was conducted against COX-1, COX-2 and LOX. The biological results demonstrated that these compounds are effective COX-1 inhibitors. Thus, the IC₅₀ values of the three most active compounds 3, 4 and 14 as COX-1 inhibitors were 1.08, 1.12 and 9.62 μΜ, respectively, compared to ibuprofen (12.7 μΜ) and naproxen (40.10 μΜ) used as control drugs. Moreover, the ulcerogenic effect of the best compounds 3, 4 and 14 were evaluated and revealed that no gastric damage was observed. Furthermore, compounds were found to be nontoxic. A molecular modeling study provided molecular insight to rationalize the COX selectivity. In summary, we discovered a novel class of selective COX-1 inhibitors that could be effectively used as potential anti-inflammatory agents.

4-(5-Amino-pyrazol-1-yl)benzenesulfonamide derivatives as novel multi-target anti-inflammatory agents endowed with inhibitory activity against COX-2, 5-LOX and carbonic anhydrase: Design, synthesis, and biological assessments

In the current medical era, the single target inhibition paradigm of drug discovery has given way to the multi-target design concept. As the most intricate pathological process, inflammation gives rise to a variety of diseases. There are several drawbacks to the single target anti-inflammatory drugs currently available. Herein, we present the design and synthesis of a novel series of 4-(5-amino-pyrazol-1-yl)benzenesulfonamide derivatives (7a-j) with COX-2, 5-LOX and carbonic anhydrase (CA) inhibitory activities as potential multi-target anti-inflammatory agents. The pharmacophoric 4-(pyrazol-1-yl)benzenesulfonamide moiety in Celecoxib was used as the core scaffold and different substituted phenyl and 2-thienyl tails were grafted via a hydrazone linker to enhance inhibitory activity against hCA IX and XII isoforms, yielding target pyrazoles 7a-j. All reported pyrazoles were evaluated for their inhibitory activity against COX-1, COX-2, and 5-LOX. Pyrazoles 7a, 7b, and 7j showed the best inhibitory activities against the COX-2 isozyme (IC₅₀ = 49, 60 and 60 nM, respectively) and against 5-LOX (IC₅₀ = 2.4, 1.9, and 2.5 μM, respectively) with excellent SI indices (COX-1/COX-2) of 212.24, 208.33, and 158.33, respectively. In addition, the inhibitory activities of pyrazoles 7a-j were evaluated against four different hCA isoforms I, II, IX, and XII. Both transmembrane hCA IX and XII isoforms were potently inhibited by pyrazoles 7a-j with K_I values in the nanomolar range; 13.0-82.1 nM and 5.8-62.0 nM, respectively. Furthermore, pyrazoles 7a and 7b with the highest COX-2 activity and selectivity indices were evaluated in vivo for their analgesic, anti-inflammatory, and ulcerogenic activities. The serum level of the inflammatory mediators was then measured in order to confirm the anti-inflammatory activities of pyrazoles 7a and 7b.

Olive Mill Wastewater Fermented with Microbial Pools as a New Potential Functional Beverage

Olive mill wastewater (OMWW) represents a by-product but also a source of biologically active compounds, and their recycling is a relevant strategy to recover income and to reduce environmental impact. The objective of the present study was to obtain a new functional beverage with a health-promoting effect starting from OMWW. Fresh OMWW were pre-treated through filtration and/or microfiltration and subjected to fermentation using strains belonging to Lactiplantibacillus plantarum, Candida boidinii and Wickerhamomyces anomalus. During fermentation, phenolic content and hydroxytyrosol were monitored. Moreover, the biological assay of microfiltered fermented OMWW was detected versus tumor cell lines and as anti-inflammatory activity. The results showed that in microfiltered OMWW, fermentation was successfully conducted, with the lowest pH values reached after 21 days. In addition, in all fermented samples, an increase in phenol and organic acid contents was detected. Particularly, in samples fermented with L. plantarum and C. boidinii in single and combined cultures, the concentration of hydroxytyrosol reached values of 925.6, 902.5 and 903.5 mg/L, respectively. Moreover, biological assays highlighted that fermentation determines an increase in the antioxidant and anti-inflammatory activity of OMWW. Lastly, an increment in the active permeability on Caco-2 cell line was also revealed. In conclusion, results of the present study confirmed that the process applied here represents an effective strategy to achieve a new functional beverage.

Discovery of 5-Methylthiazole-Thiazolidinone Conjugates as Potential Anti-Inflammatory Agents: Molecular Target Identification and In Silico Studies

A series of previously synthesized 5-benzyliden-2-(5-methylthiazole-2-ylimino)thiazoli- din-4-one were evaluated for their anti-inflammatory activity on the basis of PASS predictive outcomes. The predictive compounds were found to demonstrate moderate to good anti-inflammatory activity, and some of them displayed better activity than indomethacin used as the reference drug. Structure-activity relationships revealed that the activity of compounds depends not only on the nature of the substituent but also on its position in the benzene ring. The most active compounds were selected to investigate their possible mechanism of action. COX and LOX activity were determined and found that the title compounds were active only to COX-1 enzymes with an inhibitory effect superior to the reference drug naproxen. As for LOX inhibitory activity, the derivatives failed to show remarkable LOX inhibition. Therefore, COX-1 has been identified as the main molecular target for the anti-inflammatory activity of our compounds. The docking study against COX-1 active site revealed that the residue Arg 120 was found to be responsible for activity. In summary, the 5-thiazol-based thiazolidinone derivatives have been identified as a novel class of selective COX-1 inhibitors.

Anti-Inflammatory Potentials of β-Ketoester Derivatives of N-Ary Succinimides: In Vitro, In Vivo, and Molecular Docking Studies

Inflammation, being a well-known and complex pathological condition, is always a challenge to the human health. This research work was designed for a rationale-based anti-inflammatory study on β-ketoester derivatives of N-ary succinimides. The compounds (A–D) were synthesized by organocatalytic Michael addition. The compounds were initially screened for in vitro 5-lipoxygenase (5-LOX) and cyclooxygenase (COX-2) assays. For the in vivo activity, carrageenan-induced paw edema and arachidonic acid-induced ear edema tests were used. Furthermore, different in vivo pathways such as prostaglandins E2, histamine, leukotriene, and bradykinin were studied. The results were supported with molecular docking studies. Among the compounds, D (ethyl 1-(1-benzyl-2,5-dioxopyrrolidin-3-yl)-2-oxocyclohexane-1-carboxylate) at a concentration of 1000 μg/ml showed significant inhibitory effects of 83.67% and 78.12% against COX-2 and 5-LOX in comparison to celecoxib and zileuton, respectively. Similarly, compound D also showed excellent in vivo anti-inflammatory potential. Amongst all the compounds, D demonstrated excellent (55.92 ± 2.95%) anti-inflammatory potential at maximum tested dose (100 mg/kg) which accomplished the highest significance at 4 h following the carrageenan insertion and stayed considerable ( ${}^{\ast \ast \ast }P<0.001$ ) till the 5th hour of test sample injection. Compound D also exhibited excellent percent inhibition (63.81 ± 2.24%) at the highest dose in arachidonic acid-induced ear inflammation. On the basis of in vivo and in vitro results, compound D was subjected to various inflammation-causing agents such as histamine, prostaglandins E2, bradykinin, and leukotriene via the mouse paw edema test. Compound D revealed moderate effect (28.10 ± 1.64%) against histamine-induced paw edema while nonsignificant result (9.72 ± 3.125%) was marked for the bradykinin pathway. Compound D showed significance against edematogenic consequence of prostaglandin E2 (56.28–72.03%) and leukotriene (55.13 ± 2.25%) induced inflammation. In summary, our findings recommended that compound D possesses double acting anti-inflammatory properties inhibiting both COX and LOX pathways. Binding orientations and energy values computed via docking simulations support the results of the experimental in vitro evaluation.

Is cyclooxygenase-1 involved in neuroinflammation?

Purpose: Reactive microglia are an important hallmark of neuroinflammation. Reactive microglia release various inflammatory mediators, such as cytokines, chemokines, and prostaglandins, which are produced by enzymes like cyclooxygenases (COX). The inducible COX‐2 subtype has been associated with inflammation, whereas the constitutively expressed COX‐1 subtype is generally considered as a housekeeping enzyme. However, recent evidence suggests that COX‐1 can also be upregulated and may play a prominent role in the brain during neuroinflammation. In this review, we summarize the evidence that supports this involvement of COX‐1. Methods: Five databases were used to retrieve relevant studies that addressed COX‐1 in the context of neuroinflammation. The search resulted in 32 articles, describing in vitro, in vivo, post mortem, and in vivo imaging studies that specifically investigated the COX‐1 isoform under such conditions. Results: Reviewed literature generally indicated that the overexpression of COX‐1 was induced by an inflammatory stimulus, which resulted in an increased production of prostaglandin E2. The pharmacological inhibition of COX‐1 was shown to suppress the induction of inflammatory mediators like prostaglandin E2. Positron emission tomography (PET) imaging studies in animal models confirmed the overexpression of COX‐1 during neuroinflammation. The same imaging method, however, could not detect any upregulation of COX‐1 in patients with Alzheimer's disease. Conclusion: Taken together, studies in cultured cells and living rodents suggest that COX‐1 is involved in neuroinflammation. Most postmortem studies on human brains indicate that the concentration of COX‐1‐expressing microglial cells is increased near sites of inflammation. However, evidence for the involvement of COX‐1 in neuroinflammation in the living human brain is still largely lacking.

Formyl Peptide Receptor (FPR)1 Modulation by Resveratrol in an LPS-Induced Neuroinflammatory Animal Model

Among therapeutic approaches that have been investigated, targeting of receptors implicated in managing neuroinflammation has been described. One such family of receptors comprises the formyl peptide receptors (FPRs) whose ligands could play a role in host defense. The murine FPR gene family includes at least six members while in humans there are only three. The two most important members are the Fpr1 and Fpr2. Fpr1encodes murine FPR1, which is considered the murine orthologue of human FPR. Resveratrol, a non-flavonoid polyphenol rich in red wine and grapes, apart from its beneficial health effects and anti-inflammatory properties, has been reported to reduce neuroinflammation in different neurodegenerative disease models. Resveratrol anti-inflammatory responses involve the activation of the protein deacetylase sirtuin 1 (SIRT1) gene. In this work we have investigated in an LPS-based murine model of neuroinflammation the role of FPR1, examining not only if this receptor undergoes a reduction of its expression during neuroinflammation, but also whether treatment with resveratrol was able to modulate its expression leading to an amelioration of neuroinflammatory picture in a murine model of neuroinflammation. Results of this work showed that FPR1 together with SIRT1 resulted upregulated by resveratrol treatment and that this increase is associated with an amelioration of the neuroinflammatory picture, as demonstrated by the induction of IL-10 and IL1-RA expression and the downregulation of proinflammatory mediators, such as TNF-α and IL-1β. The expression and the modulation of FPR1 by resveratrol may be evaluated in order to propose a novel anti-inflammatory and pro-resolving therapeutic approach for the reduction of the detrimental effects associated with neuro-inflammation based neurodegenerative diseases and also as a promising strategy to promote human health by a diet rich in antioxidative bioactive compounds.

Synthesis, Inhibitory Activity, and In Silico Modeling of Selective COX-1 Inhibitors with a Quinazoline Core

Selective cyclooxygenase-1 (COX-1) inhibition has got into the spotlight with the discovery of COX-1 upregulation in various cancers and the cardioprotective role of COX-1 in control of thrombocyte aggregation. Yet, COX-1-selective inhibitors are poorly explored. Thus, three series of quinazoline derivatives were prepared and tested for their potential inhibitory activity toward COX-1 and COX-2. Of the prepared compounds, 11 exhibited interesting COX-1 selectivity, with 8 compounds being totally COX-1-selective. The IC50 value of the best quinazoline inhibitor was 64 nM. The structural features ensuring COX-1 selectivity were elucidated using in silico modeling.

A network pharmacology-based study on key pharmacological pathways and targets of Qi Fu Yin acting on Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a central nervous system (CNS) disease characterized by progressive cognitive dysfunction and memory loss. Qi Fu Yin is mainly used to treat dementia, particularly AD, in the clinic, but its comprehensive mechanisms are not known.

OBJECTIVE

In this research, we aimed to investigate the mechanisms of Qi Fu Yin in AD by network pharmacology and molecular docking.

METHODS

First, the chemical constituents in Qi Fu Yin were obtained from five databases and classified according to their structure. Targets of chemical constituents and AD-related targets were also collected from the databases. Then, overlapping genes between Qi Fu Yin and AD were identified by intersection analysis. MetaCore was used to gather enrichment information. Combination synergy analysis was performed by Cytoscape. After ligand-receptor docking, the binding affinity was verified by ADP-Glo™ kinase assay and fluorescence resonance energy transfer (FRET) assay.

RESULTS

We found 12 classes with 977 components in Qi Fu Yin. A total of 511 compounds and 577 potential target proteins in Qi Fu Yin were found to be related to AD. The pathways of Qi Fu Yin in AD included oxidative stress and immune response. There was the best binding affinity between 11 pairs of genes and compounds. Furthermore, CDK5 was inhibited by nepetin with an IC₅₀ of 3.172 μM and kaempferol with an IC₅₀ of 2.659 μM. Ceanothic acid and 18 beta-glycyrrhetinic acid inhibited GSK3β, and the IC₅₀ values were 8.732 μM and 8.06 μM, respectively.

CONCLUSION

Qi Fu Yin might alleviate Tau hyperphosphorylation by nepetin, kaempferol, ceanothic acid and 18 beta-glycyrrhetinic acid.

Three-dimensional structure of human cyclooxygenase (hCOX)-1

The beneficial effects of Cyclooxygenases (COX) inhibitors on human health have been known for thousands of years. Nevertheless, COXs, particularly COX-1, have been linked to a plethora of human diseases such as cancer, heart failure, neurological and neurodegenerative diseases only recently. COXs catalyze the first step in the biosynthesis of prostaglandins (PGs) and are among the most important mediators of inflammation. All published structural work on COX-1 deals with the ovine isoenzyme, which is easier to produce in milligram-quantities than the human enzyme and crystallizes readily. Here, we report the long-sought structure of the human cyclooxygenase-1 (hCOX-1) that we refined to an R/Rfree of 20.82/26.37, at 3.36 Å resolution. hCOX-1 structure provides a detailed picture of the enzyme active site and the residues crucial for inhibitor/substrate binding and catalytic activity. We compared hCOX-1 crystal structure with the ovine COX-1 and human COX-2 structures by using metrics based on Cartesian coordinates, backbone dihedral angles, and solvent accessibility coupled with multivariate methods. Differences and similarities among structures are discussed, with emphasis on the motifs responsible for the diversification of the various enzymes (primary structure, stability, catalytic activity, and specificity). The structure of hCOX-1 represents an essential step towards the development of new and more selective COX-1 inhibitors of enhanced therapeutic potential.

Cyclooxygenase Inhibition Safety and Efficacy in Inflammation-Based Psychiatric Disorders

According to the World Health Organization, the major psychiatric and neurodevelopmental disorders include major depression, bipolar disorder, schizophrenia, and autism spectrum disorder. The potential role of inflammation in the onset and progression of these disorders is increasingly being studied. The use of non-steroidal anti-inflammatory drugs (NSAIDs), well-known cyclooxygenase (COX) inhibitors, combined with first-choice specific drugs have been long investigated. The adjunctive administration of COX inhibitors to classic clinical treatments seems to improve the prognosis of people who suffer from psychiatric disorders. In this review, a broad overview of the use of COX inhibitors in the treatment of inflammation-based psychiatric disorders is provided. For this purpose, a critical analysis of the use of COX inhibitors in the last ten years of clinical trials of the major psychiatric disorders was carried out.

Inhibition of cyclooxygenase-1 does not reduce mortality in post-ischemic stroke rats

BACKGROUND

Ischemic stroke is one of the leading causes of mortality and morbidity. The currently available non-invasive therapeutic options are not sufficiently efficacious. Post-ischemic brain is characterized by a prominent inflammatory response. Little is known about the involvement of cyclooxygenase (COX)-1 in the pathophysiology of ischemic stroke.

OBJECTIVE

This study was undertaken to examine the effects of a highly selective COX-1 inhibitor - mofezolac - on clinical outcomes and brain inflammatory markers in post-stroke rats.

METHODS

Stroke was induced by subjecting rats to permanent middle cerebral artery occlusion (MCAO). Control rats underwent a sham surgery. Rats were treated with mofezolac (50 mg/kg, intraperitoneally [ip]) once daily for 14 days. Control animals were treated with vehicle. Body temperature (BT), neurological score (NS) and cumulative mortality were monitored at different time points. At the end of the experiment, rats were euthanized and three brain regions (hypothalamus, hippocampus and frontal cortex) were extracted. Levels of interleukin (IL)-6, prostaglandin (PG)E₂ and tumor necrosis factor (TNF)-α in these brain regions were determined by ELISA kits.

RESULTS

BT, NS and cumulative mortality were all significantly higher in post-MCAO rats than in sham-operated rats, irrespective of the treatment given. BT, NS and mortality rate did not differ significantly between mofezolac-treated and vehicle-treated sham-operated animals. BT was significantly lower in mofezolac-treated as compared to vehicle-treated post-MCAO rats. Mofezolac did not significantly alter NS in post-MCAO rats at any time-point. Cumulative 14-day mortality was non-significantly higher in mofezolac-treated as compared to vehicle-treated post-MCAO rats (48 % vs. 21 %, respectively; P =  0.184). Mostly, IL-6 and TNF-α levels did not differ between post-MCAO and sham-operated rats and were not affected by mofezolac treatment. In contrast, mofezolac significantly decreased PGE₂ levels in post-MCAO rats' brains.

CONCLUSION

Overall, these results suggest that chronic treatment with the selective COX-1 inhibitor mofezolac did not reduce morbidity or mortality in post-stroke rats.

Peripheral-to-central immune communication at the area postrema glial-barrier following bleomycin-induced sterile lung injury in adult rats

The pathways for peripheral-to-central immune communication (P → C I-comm) following sterile lung injury (SLI) are unknown. SLI evokes systemic and central inflammation, which alters central respiratory control and viscerosensory transmission in the nucleus tractus solitarii (nTS). These functional changes coincide with increased interleukin-1 beta (IL-1β) in the area postrema, a sensory circumventricular organ that connects P → C I-comm to brainstem circuits that control homeostasis. We hypothesize that IL-1β and its downstream transcriptional target, cyclooxygenase-2 (COX-2), mediate P → C I-comm in the nTS. In a rodent model of SLI induced by intratracheal bleomycin (Bleo), the sigh frequency and duration of post-sigh apnea increased in Bleo- compared to saline- treated rats one week after injury. This SLI-dependent change in respiratory control occurred concurrently with augmented IL-1β and COX-2 immunoreactivity (IR) in the funiculus separans (FS), a barrier between the AP and the brainstem. At this barrier, increases in IL-1β and COX-2 IR were confined to processes that stained for glial fibrillary acidic protein (GFAP) and that projected basolaterally to the nTS. Further, FS radial-glia did not express TNF-α or IL-6 following SLI. To test our hypothesis, we blocked central COX-1/2 activity by intracerebroventricular (ICV) infusion of Indomethacin (Ind). Continuous ICV Ind treatment prevented Bleo-dependent increases in GFAP + and IL-1β + IR, and restored characteristics of sighs that reset the rhythm. These data indicate that changes in sighs following SLI depend partially on activation of a central COX-dependent P → C I-comm via radial-glia of the FS.

Pharmacological appraisal of ligustrazine based cyclohexanone analogs as inhibitors of inflammatory markers

The targeting of pro-inflammatory enzymes becomes a therapeutic intervention when acute inflammation is proliferating in pathological conditions. This research is intended to carry out an evaluation of inhibiting and inducing enzymes with inflammatory associations with 28 cyclohexanone analogs based on the ligustrazine. Tests were undertaken with inhibitor screening assay kits using a range of synthetic compounds to investigate how they could inhibit the activity of cyclooxygenase (COX) enzymes, secretory phospholipase A₂ (sPLA₂), and lipoxygenase (LOX) enzyme. Significant and similar inhibitory activities against sPLA₂ with were noted with synthetic compounds which included 1f and 1g (IC₅₀ = 2.2 μM). The optimal inhibitory activity regarding LOX enzyme was shown with compounds 1d (IC₅₀ = 8.1 μM) and 1e (IC₅₀ = 7.5 μM). Additionally, the compounds 1b, 1d, 1e, 2n, and 2o were shown to be significant inhibitors of COX-1 activity with IC₅₀ values 0.09 to 0.7 μM. The outcomes of assays for COX inhibition demonstrated that the same compounds had a further strong inhibitive influence on the COX-2 enzyme, and certain compounds such as 1d, 1e, and 2n demonstrated enhanced potency compared with positive controls.

Lead (Pb) as a Factor Initiating and Potentiating Inflammation in Human THP-1 Macrophages

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

Bee Venom Soluble Phospholipase A2 Exerts Neuroprotective Effects in a Lipopolysaccharide-Induced Mouse Model of Alzheimer's Disease via Inhibition of Nuclear Factor-Kappa B

Neuroinflammation is important in the pathogenesis and development of Alzheimer's disease (AD). In the AD brain, microglial activation and upregulation of pro-inflammatory mediators both induce amyloid beta (Aβ) accumulation. Regulatory T cells (Tregs) and nuclear factor-kappa B (NF-κB) signaling have been implicated in AD development through their effects on neuroinflammation and microglial activation. The bee venom soluble phospholipase A2 (bv-sPLA2) enzyme is known to exert anti-inflammatory and anti-immune effects. Here, we investigated the inhibitory effects of bv-sPLA2 on memory deficiency in a lipopolysaccharide (LPS)-induced mouse model of AD. We examined whether bv-sPLA2 (0.02, 0.2, and 2 mg/kg by i.p. injection three times for 1 week) could inhibit neuroinflammation and memory impairment in LPS-treated mice (250 μg/kg by i.p. injection daily for 1 week). We also assessed the effects of bv-sPLA2 administration (0.01, 0.1, and 1 μg/ml) on LPS (1 μg/ml)-treated microglial BV-2 cells. In the LPS-injected mouse brain, sPLA2 treatment rescued memory dysfunction and decreased Aβ levels, through the downregulation of amyloidogenic proteins, and decreased the expression of inflammatory proteins and pro-inflammatory cytokines. Moreover, the LPS-mediated increase in inflammatory protein expression was attenuated bv-sPLA2 treatment in BV-2 cells. Treatment with bv-sPLA2 also downregulated signaling by NF-κB, which is considered to be an important factor in the regulation of neuroinflammatory and amyloidogenic responses, both in vivo and in vitro. Additionally, co-treatment with NF-κB (5 μM) and bv-sPLA2 (0.1 μg/ml) exerted more marked anti-inflammatory effects, compared to bv-sPLA2 treatment alone. These results indicate that bv-sPLA2 inhibits LPS-induced neuroinflammation and amyloidogenesis via inhibition of NF-κB.

Targeting COX-1 by mofezolac-based fluorescent probes for ovarian cancer detection

Biomarkers of specific targets are becoming an essential objective for clinical unmet clinical needs to improve diseases early detection and increase patient overall survival. Ovarian cancer is among the highest mortality gynecological cancers. It is asymptomatic and almost always diagnosed at advanced stage. At five years from the first diagnosis the survival rate of ovarian cancer patients is only 30%. Cyclooxygenase (COX)-1 as opposed to COX-2 is known to be overexpressed in ovarian cancer. Therefore, fluorescent probes targeting COX-1 were designed and prepared in fair to good yields for its quantitatively detection in human ovarian cancer cell lines (OVCAR-3 and SKOV-3). In particular, both cytofluorimetric and immunofluorescent experiments showed that N-[4-(9-dimethylimino-9H-benzo[a]phenoxazin-5-ylamino)butyl]-2-(3,4-bis(4-methoxyphenyl)isoxazol-5-yl)acetamide chloride (11) enters into OVCAR-3 cells and is mainly localized on the membrane containing the COX-1. Membrane fluorescence emission represents about 80% of the total fluorescence measured in the whole cell, while the non-specific labeling represents only 20%. This result indicates that the intensity of fluorescence emission is almost exclusively attributable to 11 bound to COX-1 located on the membrane. Furthermore, no diffusion inside the cell occurs. IC₅₀hCOX-1 value of 11 determined by measuring the O₂ consumption during the bis-oxygenation of the arachidonic acid catalysed by COX-1 was found to be equal to 1.8 nM. Furthermore, 11 inhibits oCOX-1 with IC₅₀ = 6.85 nM and mCOX-2 with IC₅₀ = 269.5 nM; the corresponding selectivity index SI is equal to 39.3 against oCOX-1. 11 inhibits oCOX-1 at 0 min of incubation with 91% inhibition, whereas in the same time it does not inhibit mCOX-2. Fingerprints for Ligands and Proteins (FLAP) software calculations were performed to justify 11 higher COX-1 inhibitory potency than mofezolac (COX-1 IC₅₀ = 5.1 nM), which in turn is a moiety of 11. Specifically, the two compounds bind differently in the COX-1 active site.

Inhibition of PTGS1 promotes osteogenic differentiation of adipose-derived stem cells by suppressing NF-kB signaling

BACKGROUND

Tissue inflammation is an important problem in the field of human adipose-derived stem cell (ASC)-based therapeutic bone regeneration. Many studies indicate that inflammatory cytokines are disadvantageous for osteogenic differentiation and bone formation. Therefore, overcoming inflammation would be greatly beneficial in promoting ASC-mediated bone regeneration. The present study aims to investigate the potential anti-inflammatory role of Prostaglandin G/H synthase 1 (PTGS1) during the osteogenic differentiation of ASCs.

METHODS

We performed TNFα treatment to investigate the response of PTGS1 to inflammation. Loss- and gain-of-function experiments were applied to investigate the function of PTGS1 in the osteogenic differentiation of ASCs ex vivo and in vivo. Western blot and confocal analyses were used to determine the molecular mechanism of PTGS1-regulated osteogenic differentiation.

RESULTS

Our work demonstrates that PTGS1 expression is significantly increased upon inflammatory cytokine treatment. Both ex vivo and in vivo studies indicate that PTGS1 is required for the osteogenic differentiation of ASCs. Mechanistically, we show that PTGS1 regulates osteogenesis of ASCs via modulating the NF-κB signaling pathway.

CONCLUSIONS

Collectively, this work confirms that the PTGS1-NF-κB signaling pathway is a novel molecular target for ASC-mediated regenerative medicine.

A crystallographic and theoretical study of an (E)-2-Hydroxyiminoethanone derivative: prediction of cyclooxygenase inhibition selectivity of stilbenoids by MM-PBSA and the role of atomic charge

We recently reported that the hydroxyiminoethanone derivative, (E)-OXM, behaves as a highly selective COX-1 inhibitor (COX-1 SI = 833), and also an interesting scaffold with unique characteristics. In the current study, a comprehensive crystallographic and computational study was performed to elucidate its conformational stability and pharmacological activity. Its conformational energy was studied at the B3LYP/6-311G** level of theory and compared to the single-crystal X-ray diffraction data. In addition, computational studies of three structurally different stilbenoid derivatives used as selective COX-1 or COX-2 inhibitors were undertaken to predict their COX selectivity potentials. Flexible docking was performed for all compounds at the active site of both COX-1 and COX-2 enzymes by considering some of the key residues as flexible during the docking operation. In the next step, molecular dynamic simulation and binding free energy calculations were performed by MM-PBSA. Final results were found to be highly dependent on the atomic charges of the inhibitors and the choice of force field used to calculate the atomic charges. The binding conformation of the hydroxyiminoethanone derivative is highly correlated with the type of COX isoform inhibited. Our predictive approach can truly predict the cyclooxygenase inhibition selectivity of stilbenoid inhibitors.

Microarray analysis of gene expression in the cyclooxygenase knockout mice - a connection to autism spectrum disorder

The cellular and molecular events that take place during brain development play an important role in governing function of the mature brain. Lipid-signalling molecules such as prostaglandin E₂ (PGE₂ ) play an important role in healthy brain development. Abnormalities along the COX-PGE₂ signalling pathway due to genetic or environmental causes have been linked to autism spectrum disorder (ASD). This study aims to evaluate the effect of altered COX-PGE₂ signalling on development and function of the prenatal brain using male mice lacking cyclooxygenase-1 and cyclooxygenase-2 (COX-1^-/- and COX-2^-/- ) as potential model systems of ASD. Microarray analysis was used to determine global changes in gene expression during embryonic days 16 (E16) and 19 (E19). Gene Ontology: Biological Process (GO:BP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were implemented to identify affected developmental genes and cellular processes. We found that in both knockouts the brain at E16 had nearly twice as many differentially expressed genes, and affected biological pathways containing various ASD-associated genes important in neuronal function. Interestingly, using GeneMANIA and Cytoscape we also show that the ASD-risk genes identified in both COX-1^-/- and COX-2^-/- models belong to protein-interaction networks important for brain development despite of different cellular localization of these enzymes. Lastly, we identified eight genes that belong to the Wnt signalling pathways exclusively in the COX-2^-/- mice at E16. The level of PKA-phosphorylated β-catenin (S552), a major activator of the Wnt pathway, was increased in this model, suggesting crosstalk between the COX-2-PGE₂ and Wnt pathways during early brain development. Overall, these results provide further molecular insight into the contribution of the COX-PGE₂ pathways to ASD and demonstrate that COX-1^-/- and COX-2^-/- animals might be suitable new model systems for studying the disorders.

Structural basis for selective inhibition of Cyclooxygenase-1 (COX-1) by diarylisoxazoles mofezolac and 3-(5-chlorofuran-2-yl)-5-methyl-4-phenylisoxazole (P6)

The diarylisoxazole molecular scaffold is found in several NSAIDs, especially those with high selectivity for COX-1. Here, we have determined the structural basis for COX-1 binding to two diarylisoxazoles: mofezolac, which is polar and ionizable, and 3-(5-chlorofuran-2-yl)-5-methyl-4-phenylisoxazole (P6) that has very low polarity. X-ray analysis of the crystal structures of COX-1 bound to mofezolac and 3-(5-chlorofuran-2-yl)-5-methyl-4-phenylisoxazole allowed the identification of specific binding determinants within the enzyme active site, relevant to generate structure/activity relationships for diarylisoxazole NSAIDs.