Cyclooxygenase isozymes and their gene structures and expression

The nasal basal cell population shifts toward a diseased phenotype with impaired barrier formation capacity in allergic rhinitis

BACKGROUND

The integrity of the airway epithelium is guarded by the airway basal cells that serve as progenitor cells and restore wounds in case of injury. Basal cells are a heterogenous population, and specific changes in their behavior are associated with chronic barrier disruption-mechanisms that have not been studied in detail in allergic rhinitis (AR).

OBJECTIVE

We aimed to study basal cell subtypes in AR and healthy controls.

METHODS

Single-cell RNA sequencing (scRNA-Seq) of the nasal epithelium was performed on nonallergic and house dust mite-allergic AR patients to reveal basal cell diversity and to identify allergy-related alterations. Flow cytometry, immunofluorescence staining, and in vitro experiments using primary basal cells were performed to confirm phenotypic findings at the protein level and functionally.

RESULTS

The scRNA-Seq, flow cytometry, and immunofluorescence staining revealed that basal cells are abundantly and heterogeneously present in the nasal epithelium, suggesting specialized subtypes. The total basal cell fraction within the epithelium in AR is increased compared to controls. scRNA-Seq demonstrated that potentially beneficial basal cells are missing in AR epithelium, while an activated population of allergy-associated basal cells is more dominantly present. Furthermore, our in vitro proliferation, wound healing assay and air-liquid interface cultures show that AR-associated basal cells have altered progenitor capacity compared to nonallergic basal cells.

CONCLUSIONS

The nasal basal cell population is abundant and diverse, and it shifts toward a diseased state in AR. The absence of potentially protective subtypes and the rise of a proinflammatory population suggest that basal cells are important players in maintaining epithelial barrier defects in AR.

Progress in regulating inflammatory biomaterials for intervertebral disc regeneration

Intervertebral disc degeneration (IVDD) is rising worldwide and leading to significant health issues and financial strain for patients. Traditional treatments for IVDD can alleviate pain but do not reverse disease progression, and surgical removal of the damaged disc may be required for advanced disease. The inflammatory microenvironment is a key driver in the development of disc degeneration. Suitable anti-inflammatory substances are critical for controlling inflammation in IVDD. Several treatment options, including glucocorticoids, non-steroidal anti-inflammatory drugs, and biotherapy, are being studied for their potential to reduce inflammation. However, anti-inflammatories often have a short half-life when applied directly and are quickly excreted, thus limiting their therapeutic effects. Biomaterial-based platforms are being explored as anti-inflammation therapeutic strategies for IVDD treatment. This review introduces the pathophysiology of IVDD and discusses anti-inflammatory therapeutics and the components of these unique biomaterial platforms as comprehensive treatment systems. We discuss the strengths, shortcomings, and development prospects for various biomaterials platforms used to modulate the inflammatory microenvironment, thus providing guidance for future breakthroughs in IVDD treatment.

3D-QSAR pharmacophore modeling, virtual screening, molecular docking, MD simulations, in vitro and in vivo studies to identify potential anti-hyperplasia drugs

Psoriasis is a common immune-mediated skin condition characterized by aberrant keratinocytes and cell proliferation. The purpose of this study was to explore the FDA-approved drugs by 3D-QSAR pharmacophore model and evaluate their efficiency by in-silico, in vitro, and in vivo psoriasis animal model. A 3D-QSAR pharmacophore model was developed by utilizing HypoGen algorithm using the structural features of 48 diaryl derivatives with diverse molecular patterns. The model was validated by a test set of 27 compounds, by cost analysis method, and Fischer's randomization test. The correlation coefficient of the best model (Hypo2) was 0.9601 for the training set while it was 0.805 for the test set. The selected model was taken as a 3D query for the virtual screening of over 3000 FDA-approved drugs. Compounds mapped with the pharmacophore model were further screened through molecular docking. The hits that showed the best docking results were screened through in silico skin toxicity approach. Top five hits were selected for the MD simulation studies. Based on MD simulations results, the best two hit molecules, that is, ebastine (Ebs) and mebeverine (Mbv) were selected for in vitro and in vivo antioxidant studies performed in mice. TNF-α and COX pro-inflammatory mediators, biochemical assays, histopathological analyses, and immunohistochemistry observations confirmed the anti-inflammatory response of the selected drugs. Based on these findings, it appeared that Ebs can effectively treat psoriasis-like skin lesions and down-regulate inflammatory responses which was consistent with docking predictions and could potentially be employed for further research on inflammation-related skin illnesses such as psoriasis.

Silica Nanoparticles Shed Light on Intriguing Cellular Pathways in Human Tracheal Smooth Muscle Cells: Revealing COX-2/PGE2 Production through the EGFR/Pyk2 Signaling Axis

The use of manufactured silica nanoparticles (SiNPs) has become widespread in everyday life, household products, and various industrial applications. While the harmful effects of crystalline silica on the lungs, known as silicosis or chronic pulmonary diseases, are well understood, the impact of SiNPs on the airway is not fully explored. This study aimed to investigate the potential effects of SiNPs on human tracheal smooth muscle cells (HTSMCs). Our findings revealed that SiNPs induced the expression of cyclooxygenase-2 (COX-2) mRNA/protein and the production of prostaglandin E2 (PGE2) without causing cytotoxicity. This induction was transcription-dependent, as confirmed by cell viability assays and COX-2 luciferase reporter assays. Further analysis, including Western blot with pharmacological inhibitors and siRNA interference, showed the involvement of receptor tyrosine kinase (RTK) EGF receptor (EGFR), non-RTK Pyk2, protein kinase Cα (PKCα), and p42/p44 MAPK in the induction process. Notably, EGFR activation initiated cellular signaling that led to NF-κB p65 phosphorylation and translocation into the cell nucleus, where it bound and stimulated COX-2 gene transcription. The resulting COX-2 protein triggered PGE2 production and secretion into the extracellular space. Our study demonstrated that SiNPs mediate COX-2 up-regulation and PGE2 secretion in HTSMCs through the sequential activation of the EGFR/Pyk2/PKCα/p42/p44MAPKs-dependent NF-κB signaling pathway. Since PGE2 can have both physiological bronchodilatory and anti-inflammatory effects, as well as pathological pro-inflammatory effects, the increased PGE2 production in the airway might act as a protective compensatory mechanism and/or a contributing factor during airway exposure to SiNPs.

Regulatory action of PGRMC1 on cyclic AMP-mediated COX2 expression in human endometrial cells

Human endometrial stromal cells (ESCs) undergo differentiation, known as decidualization, and endometrial epithelial cells mature around the embryo implantation stage. In the uterus, cyclooxygenase 2 (COX2), the rate-limiting enzyme that produces prostaglandin E2, is expressed in endometrial stromal and epithelial cells, and promotes decidualization of the former cells. Our recent study demonstrated that progesterone receptor membrane component 1 (PGRMC1) is downregulated during decidualization and may be involved in cellular senescence associated with decidualization via the transcription factor forkhead box protein O1 (FOXO1). Therefore, we investigated the role of PGRMC1 in COX2 expression during differentiation and maturation of endometrial stromal and epithelial cells. Inhibition or knockdown of PGRMC1 significantly enhanced differentiation stimuli-induced COX2 expression in both cell types. However, this COX2 expression was suppressed by FOXO1 knockdown or nuclear factor-kappa B (NF-κB) inhibition. Silencing of COX2 expression inhibited PGRMC1 knockdown-induced expression of decidual markers in ESCs. Thus, PGRMC1 may be linked to FOXO1- and NF-κB-mediated COX2 expression in endometrial cells. Taken together, our data suggest that downregulation of PGRMC1 expression facilitates differentiation of endometrial cells, i.e., decidualization and glandular maturation, via upregulation of COX2 expression.

Transplacental infection by bovine alphaherpesvirus type 1 induces protein expression of COX-2, iNOS and inflammatory cytokines in fetal lungs and placentas

Bovine alphaherpesvirus type 1 (BoAHV-1) is associated with respiratory and reproductive syndromes. Until present the immunologic mechanisms involved in BoAHV-1 abortion are partially known. We studied key elements of the innate immune response in the placentas and fetal lungs from cattle experimentally-inoculated with BoAHV-1. These tissues were analyzed by histopathology. Furthermore, virus identification was performed by qPCR and the expression of the inflammatory cytokines such as tumor necrosis factor-alpha, interleukin 1-alpha and inflammatory mediators like inducible nitric oxide synthase and cyclooxeganse-2 was evaluated by immunohistochemistry. The viral transplacental infection was confirmed by the detection of BoAHV-1 by qPCR in the placenta and fetal organs, which revealed mild inflammatory lesions. Inducible nitric oxide synthase immunolabelling was high in the lungs of infected fetuses and placentas, as well as for tumor necrosis factor-alpha in the pulmonary parenchyma and cyclooxeganse-2 in fetal annexes. However, the expression of interleukin 1-alpha was weak in these organs. To our knowledge, this is the first study that provides strong evidence of an early immune response to BoAHV-1 infection in the conceptus. Advances in the knowledge of the complex immunological interactions at the feto-maternal unit during BoAHV-1 infection are needed to clarify the pathogenesis of abortion.

β-Hydroxybutyrate Effects on Bovine Caruncular Epithelial Cells: A Model for Investigating the Peri-Implantation Period Disruption in Ketotic Dairy Cows

Ketosis is a metabolic disorder arising from a negative energy balance (NEB). It is characterized by high β-Hydroxybutyrate (BHBA) blood levels and associated with reduced fertility in dairy cows. To investigate the impact of BHBA on bovine caruncular epithelial cells (BCEC) in vitro, these cells were stimulated with different concentrations of BHBA. Cell metabolism and motility were examined using an MTT assay and Live-cell imaging. RT-qPCR was used to examine mRNA expressions of TNF, IL6, RELA, prostaglandin E2 synthase (PTGES2) and receptor (PTGER2) as well as integrin subunits ITGAV, ITGA6, ITGB1 and ITGB3. Stimulation with 1.8 and 2.4 mM of BHBA negatively affected cell metabolism and motility. TNF showed increased mRNA expression related to rising BHBA concentrations. IL6, RELA, ITGAV, ITGA6, ITGB1 and ITGB3 as well as PTGER2 showed no changes in mRNA expression. Stimulation with 0.6 and 1.2 mM of BHBA significantly increased the mRNA expression of PTGES2. This does not indicate a negative effect on reproductive performance because low BHBA concentrations are found in steady-state conditions. However, the results of the study show negative effects of high BHBA concentrations on the function of BCECs as well as an inflammatory response. This could negatively affect the feto-maternal communication during the peri-implantation period in ketotic dairy cows.

Comparison of preemptive etoricoxib and dexamethasone in third molar surgery - a randomized controlled clinical trial of patient-reported and clinical outcomes

OBJECTIVES

To compare preemptive single-dose etoricoxib and dexamethasone on postoperative patient satisfaction (pPS) and clinical parameters following the impacted mandibular third molar (IMTM) extraction.

MATERIALS AND METHODS

A parallel-group, triple-blinded, controlled clinical study included a total of 90 patients (n = 30), randomized to receive: etoricoxib 90 mg, dexamethasone 4 mg, or no premedication (control group) 1 h before surgery. Paracetamol 500 mg was prescribed as rescue medication (RM). Check-ups were scheduled at 24 h, 48 h, and day 7 post-surgery. At each time point, pPS was assessed using the 5-point Likert scale. RM parameters, swelling, trismus, and the occurrence of adverse events were also recorded, and patients were instructed to rate the perceived pain on Visual Analogue Scale.

RESULTS

In all the follow-up periods, data indicated significantly higher pPS scores in the preemptive medication groups when compared to the control group (p < 0.05). Both regimens delayed the first RM intake when compared to controls. In the etoricoxib group, a significantly lower total RM consumption was observed (p < 0.05). Dexamethasone significantly decreased swelling at each check-up and increased mouth opening at day 7 after the surgery (p < 0.05).

CONCLUSIONS

Preemptive etoricoxib and dexamethasone elevate pPS after IMTM surgery. Etoricoxib improves RM parameters, while dexamethasone ameliorates the patient's postoperative functional ability.

CLINICAL RELEVANCE

Preemptive etoricoxib and dexamethasone use may decrease patients' discomfort following the impacted mandibular third molar extraction.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05791721. Date of Registration: 28/03/2023 (retrospectively registered).

A Combination of Polymethoxyflavones from Citrus sinensis and Prenylflavonoids from Humulus lupulus Counteracts IL-1β-Induced Differentiated Caco-2 Cells Dysfunction via a Modulation of NF-κB/Nrf2 Activation

We here investigated the anti-inflammatory activity of a polymethoxylated flavone-containing fraction (PMFF) from Citrus sinensis and of a prenylflavonoid-containing one (PFF) from Humulus lupulus, either alone or in combination (MIX). To this end, an in vitro model of inflammatory bowel disease (IBD), consisting of differentiated, interleukin (IL)-1β-stimulated Caco-2 cells, was employed. We demonstrated that non-cytotoxic concentrations of either PMFF or PFF or MIX reduced nitric oxide (NO) production while PFF and MIX, but not PMFF, also inhibited prostaglandin E2 release. Coherently, MIX suppressed both inducible NO synthase and cyclooxygenase-2 over-expression besides NF-κB activation. Moreover, MIX increased nuclear factor erythroid 2-related factor 2 (Nrf2) activation, heme oxygenase-1 expression, restoring GSH and reactive oxygen and nitrogen species (RONs) levels. Remarkably, these effects with MIX were stronger than those produced by PMFF or PFF alone. Noteworthy, nobiletin (NOB) and xanthohumol (XTM), two of the most represented phytochemicals in PMFF and PFF, respectively, synergistically inhibited RONs production. Overall, our results demonstrate that MIX enhances the anti-inflammatory and anti-oxidative effects of the individual fractions in a model of IBD, via a mechanism involving modulation of NF-κB and Nrf2 signalling. Synergistic interactions between NOB and XTM emerge as a relevant aspect underlying this evidence.

Glucocorticoid Treatment in Acute Respiratory Distress Syndrome: An Overview on Mechanistic Insights and Clinical Benefit

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS), triggered by various pathogenic factors inside and outside the lungs, leads to diffuse lung injury and can result in respiratory failure and death, which are typical clinical critical emergencies. Severe acute pancreatitis (SAP), which has a poor clinical prognosis, is one of the most common diseases that induces ARDS. When SAP causes the body to produce a storm of inflammatory factors and even causes sepsis, clinicians will face a two-way choice between anti-inflammatory and anti-infection objectives while considering the damaged intestinal barrier and respiratory failure, which undoubtedly increases the difficulty of the diagnosis and treatment of SAP-ALI/ARDS. For a long time, many studies have been devoted to applying glucocorticoids (GCs) to control the inflammatory response and prevent and treat sepsis and ALI/ARDS. However, the specific mechanism is not precise, the clinical efficacy is uneven, and the corresponding side effects are endless. This review discusses the mechanism of action, current clinical application status, effectiveness assessment, and side effects of GCs in the treatment of ALI/ARDS (especially the subtype caused by SAP).

Cyanidin-3-O-glucoside protects intestinal epithelial cells from palmitate-induced lipotoxicity

CONTEXT

Increased free fatty acids (FFAs) levels, typical in obesity condition, can contribute to systemic lipotoxicity and inflammation adversely influencing Inflammatory Bowel Disease development and progression. Anthocyanins possess health promoting properties mainly associated to the induction of Nrf2-regulated cytoprotective proteins.

OBJECTIVE

Using a novel experimental model, we evaluated the in vitro intracellular mechanisms involved in FFAs modulation of intestinal epithelial lipotoxicity and the protective effects of cyanidin-3-O-glucoside (C3G) in Caco-2 cells.

RESULTS

Caco-2 exposed to palmitic acid (PA) in the serosal (basolateral) side showed a combined state of epithelial inflammation, inducing NF-κB pathway and downstream cytokines, that was reverted by C3G apical pre-treatment. In addition, PA altered intracellular redox status and induced reactive oxygen species that were reduced by C3G via the redox-sensitive Nrf2 signalling.

DISCUSSION AND CONCLUSION

Results suggest that anti-inflammatory properties of anthocyanins, mediated by Nrf2, could represent an interesting tool for intestinal inflammatory disorders.

Crosstalk between omega-6 oxylipins and the enteric nervous system: Implications for gut disorders?

The enteric nervous system (ENS) continues to dazzle scientists with its ability to integrate signals, from the outside as well as from the host, to accurately regulate digestive functions. Composed of neurons and enteric glial cells, the ENS interplays with numerous neighboring cells through the reception and/or the production of several types of mediators. In particular, ENS can produce and release n-6 oxylipins. These lipid mediators, derived from arachidonic acid, play a major role in inflammatory and allergic processes, but can also regulate immune and nervous system functions. As such, the study of these n-6 oxylipins on the digestive functions, their cross talk with the ENS and their implication in pathophysiological processes is in full expansion and will be discussed in this review.

Immunosuppressive reprogramming of neutrophils by lung mesenchymal cells promotes breast cancer metastasis

Neutrophils, the most abundant innate immune cells, function as crucial regulators of the adaptive immune system in diverse pathological conditions, including metastatic cancer. However, it remains largely unknown whether their immunomodulatory functions are intrinsic or acquired within the pathological tissue environment. Here, using mouse models of metastatic breast cancer in the lungs, we show that, although neutrophils isolated from bone marrow (BM) or blood are minimally immunosuppressive, lung-infiltrating neutrophils are robustly suppressive of both T cells and natural killer (NK) cells. We found that this tissue-specific immunosuppressive capacity of neutrophils exists in the steady state and is reinforced by tumor-associated inflammation. Acquisition of potent immunosuppression activity by lung-infiltrating neutrophils was endowed by the lung-resident stroma, specifically CD140a+ mesenchymal cells (MCs) and largely via prostaglandin-endoperoxide synthase 2 (PTGS2), the rate-limiting enzyme for prostaglandin E2 (PGE2) biosynthesis. MC-specific deletion of Ptgs2 or pharmacological inhibition of PGE2 receptors reversed lung neutrophil-mediated immunosuppression and mitigated lung metastasis of breast cancer in vivo. These lung stroma-targeting strategies substantially improved the therapeutic efficacy of adoptive T cell-based immunotherapy in treating metastatic disease in mice. Collectively, our results reveal that the immunoregulatory effects of neutrophils are induced by tissue-resident stroma and that targeting tissue-specific stromal factors represents an effective approach to boost tissue-resident immunity against metastatic disease.

The Link between Prostanoids and Cardiovascular Diseases

Cardiovascular diseases are the leading cause of global deaths, and many risk factors contribute to their pathogenesis. In this context, prostanoids, which derive from arachidonic acid, have attracted attention for their involvement in cardiovascular homeostasis and inflammatory processes. Prostanoids are the target of several drugs, but it has been shown that some of them increase the risk of thrombosis. Overall, many studies have shown that prostanoids are tightly associated with cardiovascular diseases and that several polymorphisms in genes involved in their synthesis and function increase the risk of developing these pathologies. In this review, we focus on molecular mechanisms linking prostanoids to cardiovascular diseases and we provide an overview of genetic polymorphisms that increase the risk for cardiovascular disease.

Protective effect of berberine against LPS-induced injury in the intestine: a review

Sepsis is a systemic inflammatory condition caused by an unbalanced immunological response to infection, which affects numerous organs, including the intestines. Lipopolysaccharide (LPS; also known as endotoxin), a substance found in Gram-negative bacteria, plays a major role in sepsis and is mostly responsible for the disease's morbidity and mortality. Berberine is an isoquinoline alkaloid found in a variety of plant species that has anti-inflammatory properties. For many years, berberine has been used to treat intestinal inflammation and infection. Berberine has been reported to reduce LPS-induced intestinal damage. The potential pathways through which berberine protects against LPS-induced intestinal damage by inhibiting NF-κB, suppressing MAPK, modulating ApoM/S1P pathway, inhibiting COX-2, modulating Wnt/Beta-Catenin signaling pathway, and/or increasing ZIP14 expression are reviewed.Abbreviations: LPS, lipopolysaccharide; TLR, Toll-like receptor; MD-2, myeloid differentiation factor 2; CD14, cluster of differentiation 14; LBP, lipopolysaccharide-binding protein; MYD88, myeloid differentiation primary response 88; NF-κB, nuclear factor kappa light-chain enhancer of activated B cells; MAPK, mitogen-activated protein kinase; IL, interleukin; TNFα, tumor necrosis factor-alpha; Caco-2, cyanocobalamin uptake by human colon adenocarcinoma cell line; MLCK, myosin light-chain kinase; TJ, tight junction; IκBα, nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha; IBS, irritable bowel syndrome; ERK, extracellular signal-regulated kinase; JNK, c-Jun N-terminal kinase (JNK; GVB, gut-vascular barrier; ApoM, apolipoprotein M; S1P, sphingosine-1-phosphate; VE-cadherin, vascular endothelial cadherin; AJ, adherens junction; PV1, plasmalemma vesicle-associated protein-1; HDL, high-density lipoprotein; Wnt, wingless-related integration site; Fzd, 7-span transmembrane protein Frizzled; LRP, low-density lipoprotein receptor-related protein; TEER, transendothelial/transepithelial electrical resistance; COX-2, cyclooxygenase-2; iNOS, inducible nitric oxide synthase; IGF, insulin-like growth factor; IGFBP, insulin-like growth factor-binding protein; ZIP, Zrt-Irt-like protein; PPAR, peroxisome proliferator-activated receptors; p-PPAR, phosphorylated-peroxisome proliferator-activated receptors; ATF, activating transcription factors; SOD, superoxide dismutase; GSH-Px, glutathione peroxidase; SARA, subacute ruminal acidosis; IPEC-J2, porcine intestinal epithelial cells; ALI, acute lung injury; ARDS, acute respiratory distress syndrome.

Regulation of Cyclooxygenase-2 Expression in Human T Cells by Glucocorticoid Receptor-Mediated Transrepression of Nuclear Factor of Activated T Cells

Cyclooxygenase (COX) is the key enzyme in prostanoid synthesis from arachidonic acid (AA). Two isoforms, named COX-1 and COX-2, are expressed in mammalian tissues. The expression of COX-2 isoform is induced by several stimuli including cytokines and mitogens, and this induction is inhibited by glucocorticoids (GCs). We have previously shown that the transcriptional induction of COX-2 occurs early after T cell receptor (TCR) triggering, suggesting functional implications of this enzyme in T cell activation. Here, we show that dexamethasone (Dex) inhibits nuclear factor of activated T cells (NFAT)-mediated COX-2 transcriptional induction upon T cell activation. This effect is dependent on the presence of the GC receptor (GR), but independent of a functional DNA binding domain, as the activation-deficient GRLS7 mutant was as effective as the wild-type GR in the repression of NFAT-dependent transcription. Dex treatment did not disturb NFAT dephosphorylation, but interfered with activation mediated by the N-terminal transactivation domain (TAD) of NFAT, thus pointing to a negative cross-talk between GR and NFAT at the nuclear level. These results unveil the ability of GCs to interfere with NFAT activation and the induction of pro-inflammatory genes such as COX-2, and explain some of their immunomodulatory properties in activated human T cells.

Effect of intermittency factor on singlet oxygen and PGE2 formation in azulene-mediated photodynamic therapy: A preliminary study

In photodynamic therapy, intermittent irradiation modes that incorporate an interval between pulses are believed to decrease the effect of hypoxia by permitting an interval of re-oxygenation. The effect of the irradiation intermittency factor (the ratio of the irradiation pulse time to the total irradiation time) on singlet oxygen formation and inflammatory cytokine production was examined using azulene as a photosensitizer. Effects of difference intermittency factor on singlet oxygen formation and inflammatory cytokine were examined. Azulene solutions (1/10 μM) were irradiated with a 638-nm 500 mW diode laser in fractionation (intermittency factor of 5 or 9) or continuous mode using 50 mW/cm² at 4 or 8 J/cm². Singlet oxygen measurement was performed using a dimethyl anthracene probe. Peripheral blood mononuclear cells (PBMC) were stimulated by 10 ng/ml rhTNF-α for 6 h, before addition of 1 and 10 μM azulene solutions and irradiation. PGE₂ measurement was undertaken using a human PGE₂ ELISA kit. Kruskal-Wallis with Dunn Bonferroni test was used for statistical analyses at p < 0.05.Irradiation of 1 μM azulene+4 J/cm²+intermittency factor of 9 increased singlet oxygen 3-fold (p < 0.0001). Irradiation of 10 μM azulene at either 4 J/cm²+intermittency of 9 or 8 J/cm²+intermittency factor of 5 reduced PGE₂ expression in PBMCs to non-inflamed levels. Thus, at 50 mW/cm², 10 μM azulene-mediated photodynamic therapy with a high intermittency factor and a low energy density generated sufficient singlet oxygen to suppress PGE₂ in Inflamed PBMCs.

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Different intermittency factors can stimulate ROS formation differently.

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Relative high intermittency factor with azulene induces high ROS formation.

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Relative high intermittency factor with low energy density inhibits PGE₂ production.

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Azulene-based photodynamic therapy suppresses inflammation.

The Impact of Corticosteroid Injection Timing on Infection Rates Following Spine Surgery: A Systematic Review and Meta-Analysis

STUDY DESIGN/SETTING

Systematic review/meta-analysis.

OBJECTIVES

The objective of this review was to assess how the risk of infection following lumbar spine surgery varies as a function of the timing of preoperative corticosteroid spinal injections (CSIs).

METHODS

A systematic review and meta-analysis was performed in accordance with the PRISMA guidelines. PubMed and EMBASE databases were searched and data was pooled for meta-analysis.

RESULTS

Six studies were identified for inclusion. Two (33.3%) demonstrated a significant relationship between the timing of preoperative CSIs and the risk of postoperative infection, while 4 (66.7%) demonstrated no impact. A total of 2.5% (110/4,448) of patients who underwent CSI <1 month before surgery experienced a postoperative infection, as compared to 1.2% (1,466/120, 943) of controls, which was statistically significant (RR = 1.986 95% CI 1.202-3.282 P = 0.007). A total of 1.6% (25/1,600) of patients who underwent CSI 0-3 months before surgery experienced a postoperative infection, as compared to 1.6% (201/12, 845) of controls (RR = 0.887 95% CI 0.586-1.341, P = 0.569). A total of 1.1% (199/17 870) of patients who underwent CSI 3-6 months before surgery experienced a postoperative infection, as compared to 1.3% (1,382/102, 572) of controls (RR = 1.053 95% CI 0.704-1.575, P = 0.802). Differences in infection risk for 0-3 months and 3-6 months were not statistically significant.

CONCLUSIONS

CSIs <1 month prior to lumbar spine surgery are a significant risk factor for infection, while CSIs beyond that point showed no such association. Surgeons should consider avoiding CSIs <1 month of the use of CSIs of the spine.

Label-free LC-MS/MS proteomics analyses reveal proteomic changes in oxidative stress and the SOD antioxidant strategy in TM cells

Background

Treatment for glaucoma has traditionally been limited to reducing intraocular pressure (IOP). Inhibiting oxidative stress in the trabecular meshwork (TM) is regarded as a new treatment for glaucoma; however, the effects do not meet expectations. Exploring the mechanism by which oxidative stress and antioxidant stress occur in TM cells will offer clues to aid the development of new treatments.

Methods and results

In our study, we cultured TM cells and used H₂O₂ and SOD to induce and inhibit oxidative stress, respectively. Label-free LC–MS/MS quantitative proteomic analysis was conducted to analyze the differentially expressed proteins and relevant signaling pathways. A total of 24 upregulated proteins and 18 downregulated proteins were identified under oxidative stress. PTGS2, TGFβr2 and ICAM-1 are the key proteins. The PTGS2/NF-ĸb pathway, TGF-β/Smad signaling pathway and AGE-RAGE signaling pathway in diabetic complications may be the major signaling pathways under conditions of ROS-induced damage in TM cells. Seventy-eight proteins were upregulated and 73 proteins were downregulated under antioxidant stress in TM cells. The key protein was ICAM-1, which participates in the African trypanosomiasis pathway, one of the most important pathways under antioxidant stress. Combining the results of the Venn diagram with protein–protein interactions (PPIs), ICAM-1 was identified as the major protein. Cell Counting Kit-8 (CCK-8) and western blotting (WB) were used to reveal that suppressing the expression of ICAM-1 would improve the survival of TM cells.

Conclusions

Key proteins and signaling pathways play important roles in the mechanisms of oxidative stress and antioxidant strategies in TM cells. ICAM-1 knockdown can suppress the apoptosis of TM cells induced by H₂O_2, which may reveal new therapeutic targets and biomarkers for glaucoma.

Prenatal Activation of Glucocorticoid Receptors Induces Memory Impairment in a Sex-Dependent Manner: Role of Cyclooxygenase-2

Prenatal exposure to dexamethasone (DEX) results in long-lasting effects on cognitive functions such as learning and memory impairment. However, the mechanisms underlying these DEX-induced deleterious effects are not well known. Here, we assessed whether cyclooxygenase-2 (COX-2) is involved in the impact of prenatal exposure to DEX on learning and memory during adulthood. Pregnant Sprague-Dawley rats received daily injections of either DEX (0.2 mg/kg; i.p.) or saline from gestation day (GD) 14 until GD21. Gene and protein expression of COX-2, as well as presynaptic (synaptophysin) and postsynaptic (postsynaptic density protein-95) proteins, were monitored in the dorsal and ventral hippocampi of adult male and female offspring. A different cohort of adult male and female rat offspring was given daily injections of either vehicle or a specific COX-2 inhibitor (celecoxib 10 mg/kg, i.p.) for 5 consecutive days and was subsequently subjected to Morris water maze memory test. Prenatal DEX enhanced the expression of COX-2 protein and cox-2 mRNA in the dorsal hippocampus of adult female but not male rats. This enhanced COX-2 expression was associated with reduced expression in pre- and postsynaptic proteins and altered memory acquisition and retention. Administration of COX-2-specific inhibitor alleviated prenatal DEX-induced memory impairment in adult female rats. This study suggests that prenatal activation of glucocorticoid receptors stimulates COX-2 gene and protein expression and impairs hippocampal-dependent spatial memory in female but not male rat offspring. Furthermore, COX-2 selective inhibitors can be used to alleviate the long-lasting deleterious effects of corticosteroid medication during pregnancy.

Tea Seed Kaempferol Triglycoside Attenuates LPS-Induced Systemic Inflammation and Ameliorates Cognitive Impairments in a Mouse Model

(1) Background: The current research intended to obtain functional compounds from agricultural by-products. A functional tea seed flavonoid, kaempferol-3-O-[2-O-β-d-xylopyranosyl-6-O-α-L-rhanmopyranosyl]-β-d-glucopyranoside (KXRG), was isolated from tea seed dregs. We further determined its chemical structure and evaluated the protective effects of KXRG against local and systemic inflammation in vivo; (2) Methods: First, cytotoxicity and proinflammatory cytokine release were examined in a cell-culture system. The biological activities of KXRG were investigated in a mouse model of ear edema, and from inflammatory damage to organs as demonstrated by histologic examination, in addition to brain function evaluation using the Y-maze test. Serum biochemical analysis and western blotting were utilized to explore the related cellular factors; (3) Results: KXRG inhibited IL-6 in RAW264.7 cells at a non-toxic concentration. Further experiments confirmed that KXRG exerted a stronger effect than indomethacin in terms of the prevention of 12-O-tetradecanoylphorbol acetate (TPA)-induced ear inflammation in a mouse model. KXRG feeding significantly prevented LPS-induced small intestine, liver, and kidney inflammatory damage, as demonstrated by histologic examination. KXRG also significantly improved LPS-induced cognitive impairments. Serum biochemical analysis showed that KXRG elevated antioxidant capacity and reduced levels of proinflammatory cytokines. Western blotting revealed that KXRG reduced the COX-2 expression induced by LPS in mouse tissues; (4) Conclusions: KXRG can be purified from agricultural waste, and hence it is inexpensive, with large amounts of raw materials available. Thus, KXRG has strong potential for further development as a wide-use anti-systemic inflammation drug to prevent human disease.

CBS-H2S axis preserves the intestinal barrier function by inhibiting COX-2 through sulfhydrating human antigen R in colitis

INTRODUCTION

Lipopolysaccharide (LPS) causes lesions of the epithelial barrier, which allows translocation of pathogens from the intestinal lumen to the host's circulation. Hydrogen sulfide (H₂S) regulates multiple physiological and pathological processes in colonic epithelial tissue, and CBS-H₂S axis involved in multiple gastrointestinal disorder. However, the mechanism underlying the effect of the CBS-H₂S axis on the intestinal and systemic inflammation in colitis remains to be illustrated.

OBJECTIVES

To investigate the effect of CBS-H₂S axis on the intestinal and systematic inflammation related injuries in LPS induced colitis and the underlying mechanisms.

METHODS

Wild type and CBS^-/+ mice were used to evaluate the effect of endogenous and exogenous H₂S on LPS-induced colitis in vivo. Cytokine quantitative antibody array, western blot and real-time PCR were applied to detect the key cytokines in the mechanism of action. Biotin switch of S-sulfhydration, CRISPR/Cas9 mediated knockout, immunofluorescence and ActD chase assay were used in the in vitro experiment to further clarify the molecular mechanisms.

RESULTS

H₂S significantly alleviated the symptoms of LPS-induced colitis in vivo and attenuated the increase of COX-2 expression. The sulfhydrated HuR increased when CBS express normally or GYY4137 was administered. While after knocking kown CBS, the expression of COX-2 in mice colon increased significantly, and the sulfhydration level of HuR decreased. The results in vitro illustrated that HuR can increase the stability of COX-2 mRNA, and the decrease of COX-2 were due to increased sulfhydration of HuR rather than the reduction of total HuR levels.

CONCLUSION

These results indicated that CBS-H₂S axis played an important role in protecting intestinal barrier function in colitis. CBS-H₂S axis increases the sulfhydration level of HuR, by which reduces the binding of HuR with COX-2 mRNA and inhibited the expression of COX-2.

Prostaglandin E2 and Receptors: Insight Into Tumorigenesis, Tumor Progression, and Treatment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common primary liver cancer with ∼750,000 annual incidence rates globally. PGE2, usually known as a pro-inflammatory cytokine, is over-expressed in various human malignancies including HCC. PGE2 binds to EP receptors in HCC cells to influence tumorigenesis or enhance tumor progression through multiple pathways such as EP1-PKC-MAPK, EP2-PKA-GSK3β, and EP4-PKA-CREB. In the progression of hepatocellular carcinoma, PGE2 can promote the proliferation and migration of liver cancer cells by affecting hepatocytes directly and the tumor microenvironment (TME) through ERK/COX-2/PGE2 signal pathway in hepatic stellate cells (HSC). For the treatment of hepatocellular carcinoma, there are drugs such as T7 peptide and EP1 antagonist ONO-8711 targeting Cox-2/PGE2 axis to inhibit tumor progression. In conclusion, PGE2 has been shown to be a traditional target with pleiotropic effects in tumorigenesis and progression of HCC that could be used to develop a new potential clinical impact. For the treatment study focusing on the COX-PGE2 axis, the exclusive usage of non-steroidal anti-inflammatory agents (NSAIDs) or COX-2-inhibitors may be replaced by a combination of selective EP antagonists and traditional anti-tumoral drugs to alleviate severe side effects and achieve better outcomes.

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.

Gut-Restricted Selective Cyclooxygenase-2 (COX-2) Inhibitors for Chemoprevention of Colorectal Cancer

Selective cyclooxygenase (COX)-2 inhibitors have been extensively studied for colorectal cancer (CRC) chemoprevention. Celecoxib has been reported to reduce the incidence of colorectal adenomas and CRC but is also associated with an increased risk of cardiovascular events. Here, we report a series of gut-restricted, selective COX-2 inhibitors characterized by high colonic exposure and minimized systemic exposure. By establishing acute ex vivo ¹⁸F-FDG uptake attenuation as an efficacy proxy, we identified a subset of analogues that demonstrated statistically significant in vivo dose-dependent inhibition of adenoma progression and survival extension in an APC^min/+ mouse model. However, in vitro-in vivo correlation analysis showed their chemoprotective effects were driven by residual systemic COX-2 inhibition, rationalizing their less than expected efficacies and highlighting the challenges associated with COX-2-mediated CRC disease chemoprevention.

Intersecting Mechanisms of Hypoxia and Prostaglandin E2-Mediated Inflammation in the Comparative Biology of Oral Squamous Cell Carcinoma

The importance of inflammation in the pathogenesis of cancer was first proposed by Rudolph Virchow over 150 years ago, and our understanding of its significance has grown over decades of biomedical research. The arachidonic acid pathway of inflammation, including cyclooxygenase (COX) enzymes, PGE2 synthase enzymes, prostaglandin E2 (PGE2) and PGE2 receptors has been extensively studied and has been associated with different diseases and different types of cancers, including oral squamous cell carcinoma (OSCC). In addition to inflammation in the tumour microenvironment, low oxygen levels (hypoxia) within tumours have also been shown to contribute to tumour progression. Understandably, most of our OSCC knowledge comes from study of this aggressive cancer in human patients and in experimental rodent models. However, domestic animals develop OSCC spontaneously and this is an important, and difficult to treat, form of cancer in veterinary medicine. The primary goal of this review article is to explore the available evidence regarding interaction between hypoxia and the arachidonic acid pathway of inflammation during malignant behaviour of OSCC. Overlapping mechanisms in hypoxia and inflammation can contribute to tumour growth, angiogenesis, and, importantly, resistance to therapy. The benefits and controversies of anti-inflammatory and anti-angiogenic therapies for human and animal OSCC patients will be discussed, including conventional pharmaceutical agents as well as natural products.

Phytosterols: Targeting Neuroinflammation in Neurodegeneration

Plant-derived sterols, phytosterols, are well known for their cholesterol-lowering activity in serum and their anti-inflammatory activities. Recently, phytosterols have received considerable attention due to their beneficial effects on various non-communicable diseases, and recommended use as daily dietary components. The signaling pathways mediated in the brain by phytosterols have been evaluated, but little is known about their effects on neuroinflammation, and no clinical studies have been undertaken on phytosterols of interest. In this review, we discuss the beneficial roles of phytosterols, including their attenuating effects on inflammation, blood cholesterol levels, and hallmarks of the disease, and their regulatory effects on neuroinflammatory disease pathways. Despite recent advancements made in phytosterol pharmacology, some critical questions remain unanswered. Therefore, we have tried to highlight the potential of phytosterols as viable therapeutics against neuroinflammation and to direct future research with respect to clinical applications.

Cyclooxygenase-2 Glycosylation Is Affected by Peroxynitrite in Endothelial Cells: Impact on Enzyme Activity and Degradation

The exposure of human endothelial cells to 3-morpholinosydnonimine (SIN-1) induced the expression of cyclooxygenase-2 (COX-2) in a dose- and time-dependent manner. Interestingly, after a prolonged incubation (>8 h) several proteoforms were visualized by Western blot, corresponding to different states of glycosylation of the protein. This effect was specific for SIN-1 that generates peroxynitrite and it was not detected with other nitric oxide-donors. Metabolic labeling experiments using 35S or cycloheximide suggested that the formation of hypoglycosylated COX-2 was dependent on de novo synthesis of the protein rather than the deglycosylation of the native protein. Moreover, SIN-1 reduced the activity of the hexokinase, the enzyme responsible for the first step of glycolysis. The hypoglycosylated COX-2 induced by SIN-1 showed a reduced capacity to generate prostaglandins and the activity was only partially recovered after immunoprecipitation. Finally, hypoglycosylated COX-2 showed a more rapid rate of degradation compared to COX-2 induced by IL-1α and an alteration in the localization with an accumulation mainly detected in the nuclear membrane. Our results have important implication to understand the effect of peroxynitrite on COX-2 expression and activity, and they may help to identify new pharmacological tools direct to increase COX-2 degradation or to inhibit its activity.

Genetic Variations in Prostaglandin E2 Pathway Identified as Susceptibility Biomarkers for Gastric Cancer in an Intermediate Risk European Country

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

Design and synthesis of pyrimidine-5-carbonitrile hybrids as COX-2 inhibitors: Anti-inflammatory activity, ulcerogenic liability, histopathological and docking studies

Two new series of 1,3,4-oxadiazole and coumarin derivatives based on pyrimidine-5-carbonitrile scaffold have been synthesized and evaluated for their COX-1/COX-2 inhibitory activity. Compounds 10c, 10e, 10h-j, 14e-f, 14i and 16 were found to be the most potent and selective inhibitors of COX-2 (IC₅₀ 0.041-0.081 μM, SI 139.74-321.95). Eight compounds were further investigated for their in vivo anti-inflammatory activity. The most active derivatives 10c, 10j and 14e displayed superior in vivo anti-inflammatory activity (% edema inhibition 39.3-48.3, 1 h; 58.4-60.5, 2 h; 70.8-83.2, 3 h; 78.9-89.5, 4 h) to the reference drug celecoxib (% edema inhibition 38.0, 1 h; 48.8, 2 h; 58.4, 3 h; 65.4, 4 h). These derivatives were also tested for their ulcerogenic liability, compound 10j showed better safety profile with reference to celecoxib while 10c and 14e exhibited mild lesions. Molecular docking studies of 10c, 10j, and 14e in the COX-2 active site revealed similar orientation and binding interactions as selective COX-2 inhibitors with a higher liability to access the selectivity side pocket.

Sphingosine 1-Phosphate Induces Cyclooxygenase-2/Prostaglandin E2 Expression via PKCα-dependent Mitogen-Activated Protein Kinases and NF-κB Cascade in Human Cardiac Fibroblasts

In the regions of tissue injuries and inflammatory diseases, sphingosine 1-phosphate (S1P), a proinflammatory mediator, is increased. S1P may induce the upregulation of cyclooxygenase-2 (COX-2)/prostaglandin E₂ (PGE₂) system in various types of cells to exacerbate heart inflammation. However, the detailed molecular mechanisms by which S1P induces COX-2 expression in human cardiac fibroblasts (HCFs) remain unknown. HCFs were incubated with S1P and analyzed by Western blotting, real time-Polymerase chain reaction (RT-PCR), and immunofluorescent staining. Our results indicated that S1P activated S1PR_1/3-dependent transcriptional activity to induce COX-2 expression and PGE₂ production. S1P recruited and activated PTX-sensitive G_i or -insensitive G_q protein-coupled S1PR and then stimulated PKCα-dependent phosphorylation of p42/p44 MAPK, p38 MAPK, and JNK1/2, leading to activating transcription factor NF-κB. Moreover, S1P-activated NF-κB was translocated into the nucleus and bound to its corresponding binding sites on COX-2 promoters determined by chromatin immunoprecipitation (ChIP) and promoter-reporter assays, thereby turning on COX-2 gene transcription associated with PGE₂ production in HCFs. These results concluded that in HCFs, activation of NF-κB by PKCα-mediated MAPK cascades was essential for S1P-induced up-regulation of the COX-2/PGE₂ system. Understanding the mechanisms of COX-2 expression and PGE₂ production regulated by the S1P/S1PRs system on cardiac fibroblasts may provide rationally therapeutic interventions for heart injury or inflammatory diseases.

The -1195A>G polymorphism in Ciclooxygenase-2 gene is associated with lower risk of endometriosis

OBJECTIVES

This study aimed to evaluate the potential role of the PTGS2 single nucleotide polymorphisms (SNPs) -1195 A>G and +8473 T>C in endometriosis' development, and characterizing their association with the prognostic features of the disease.

STUDY DESIGN

DNA from 254 women with endometriosis and 267 controls, recruited from two reference hospitals from the Brazilian public health system, were genotyped using TaqMan allelic discrimination assays. The association between SNPs and endometriosis features was evaluated by multivariate logistic regression, using the adjusted odds ratios (OR) with their respective 95% confidence intervals (95% CI).

RESULTS AND CONCLUSION

There were significant differences between cases and controls regarding age (P < 0.001), body mass index (BMI) (P = 0.001), educational level (P < 0.001), physical activity (P = 0.003), smoking status (P < 0.001), contraception use (P = 0.02), family history of endometriosis (P = 0.002) and all symptoms (P < 0.001). The distribution of -1195 A > G was statistically different between the groups, suggesting a lower risk of developing the disease for the carriers of the -1195 GG genotype (OR = 0.19; 95% CI = 0.04 - 0.93). No differences were found for the +8473 T>C between the two groups and neither in prognostic features of the disease for both PTGS2 SNPs. In conclusion, PTGS2 -1195A>G SNP was negatively associated with development of endometriosis and the two groups were statistically different regarding age, BMI, educational level, physical activity, smoking status, contraception use, history of endometriosis and all endometriosis symptoms.

Expression of Cyclooxygenase-2 in Human Epithelial Skin Lesions: A Systematic Review of Immunohistochemical Studies

Permanent, elevated expression of cyclooxygenase-2 (COX-2) in keratinocytes of epidermis can stimulate its hyperplasia and constitute a factor promoting cancer development, as demonstrated in animal models. Intratumoral level and localization of COX-2 in epithelial lesions of human skin was examined immunohistochemically in 26 studies. In squamous cell carcinomas (SCCs), strong staining was observed with great compatibility. High COX-2 detectability throughout the entire tumor mass could be helpful in the finding of SCC cells. However, in basal cell carcinomas, and precancerous lesions, frequency and detection level of this protein, as well as the type and/or localization of stained cells within the tumor, varied among different research groups. The discrepancies may be due to the heterogeneity of each of these 2 groups of lesions. However, differences in COX-2 staining in normal skin indicate also possible methodological reasons. In general, COX-2 levels were significantly decreased in basal cell carcinomas compared with SCCs, which could be used in the differential diagnosis of these cancers. Reduced, although heterogenous, COX-2 expression in precancerous lesions may suggest its association with SCC development. These observations are consistent with data on the efficacy of preventive and therapeutic effects of nonsteroidal anti-inflammatory drugs that are COX-2 inhibitors.

Role of water in cyclooxygenase catalysis and design of anti-inflammatory agents targeting two sites of the enzyme

While designing the anti-inflammatory agents targeting cyclooxygenase-2 (COX-2), we first identified a water loop around the heme playing critical role in the enzyme catalysis. The results of molecular dynamic studies supported by the strong hydrogen-bonding equilibria of the participating atoms, radical stabilization energies, the pK_a of the H-donor/acceptor sites and the cyclooxygenase activity of pertinent muCOX-2 ravelled the working of the water–peptide channel for coordinating the flow of H·/electron between the heme and Y385. Based on the working of H·/electron transfer channel between the 12.5 Å distant radical generation and the radical disposal sites, a series of molecules was designed and synthesized. Among this category of compounds, an appreciably potent anti-inflammatory agent exhibiting IC₅₀ 0.06 μM against COX-2 and reversing the formalin induced analgesia and carageenan induced inflammation in mice by 90% was identified. Further it was revealed that, justifying its bidentate design, the compound targets water loop (heme bound site) and the arachidonic acid binding pockets of COX-2.

Pharmacological Characterization of the Microsomal Prostaglandin E2 Synthase-1 Inhibitor AF3485 In Vitro and In Vivo

Rationale

The development of inhibitors of microsomal prostaglandin (PG)E₂ synthase-1 (mPGES-1) was driven by the promise of attaining antiinflammatory agents with a safe cardiovascular profile because of the possible diversion of the accumulated substrate, PGH₂, towards prostacyclin (PGI₂).

Objectives

We studied the effect of the human mPGES-1 inhibitor, AF3485 (a benzamide derivative) on prostanoid biosynthesis in human whole blood in vitro. To characterize possible off-target effects of the compound, we evaluated: i)the impact of its administration on the systemic biosynthesis of prostanoids in a model of complete Freund's adjuvant (CFA)-induced monoarthritis in rats; ii) the effects on cyclooxygenase (COX)-2 expression and the biosynthesis of prostanoids in human monocytes and human umbilical vein endothelial cells (HUVECs) in vitro.

Methods

Prostanoids were assessed in different cellular models by immunoassays. The effect of the administration of AF3485 (30 and 100 mg/kg,i.p.) or celecoxib (20mg/kg, i.p.), for 3 days, on the urinary levels of enzymatic metabolites of prostanoids, PGE-M, PGI-M, and TX-M were assessed by LC-MS.

Results

In LPS-stimulated whole blood, AF3485 inhibited PGE₂ biosynthesis, in a concentration-dependent fashion. At 100μM, PGE₂ levels were reduced by 66.06 ± 3.30%, associated with a lower extent of TXB₂ inhibition (40.56 ± 5.77%). AF3485 administration to CFA-treated rats significantly reduced PGE-M (P < 0.01) and TX-M (P < 0.05) similar to the selective COX-2 inhibitor, celecoxib. In contrast, AF3485 induced a significant (P < 0.05) increase of urinary PGI-M while it was reduced by celecoxib. In LPS-stimulated human monocytes, AF3485 inhibited PGE₂ biosynthesis with an IC₅₀ value of 3.03 µM (95% CI:0.5–8.75). At 1μM, AF3485 enhanced TXB₂ while at higher concentrations, the drug caused a concentration-dependent inhibition of TXB₂. At 100 μM, maximal inhibition of the two prostanoids was associated with the downregulation of COX-2 protein by 86%. These effects did not involve AMPK pathway activation, IkB stabilization, or PPARγ activation. In HUVEC, AF3485 at 100 μM caused a significant (P < 0.05) induction of COX-2 protein associated with enhanced PGI₂ production. These effects were reversed by the PPARγ antagonist GW9662.

Conclusions

The inhibitor of human mPGES-1 AF3485 is a novel antiinflammatory compound which can also modulate COX-2 induction by inflammatory stimuli. The compound also induces endothelial COX-2-dependent PGI₂ production via PPARγ activation, both in vitro and in vivo, which might translate into a protective effect for the cardiovascular system.

Immunohistochemical detectability of cyclooxygenase-2 expression in cells of human melanocytic skin lesions: A methodological review

Increased cyclooxygenase-2 (COX-2) expression is thought to support tumorigenesis through various mechanisms and is analyzed as a potential cancer marker. In 18 studies, COX-2 expression in melanocytic lesions of human skin was examined immunohistochemically. However, results obtained by individual research groups differ in terms of detection frequency and level of this protein, as well as localization of stained cells within tumor. Possible reasons for the discrepancies are analyzed in this review: the application of different antibodies, the use of standard histopathological sections or tissue microarrays and the analyzes of staining results based on different algorithms. COX-2 level is significantly lower in nevi than in melanomas, increases gradually with progression of these malignant cancers and reaches the highest values in metastases. These gradual changes in COX-2 expression appear to be difficult to analyze based only on subjective assessment of staining intensity. The most convergent data were obtained using antibodies for N-terminal fragments of COX-2 protein and analyzing results based on calculation of percentage fraction of positive cells. The extent of stained area in specimen thus appears to be more important than the intensity of staining in terms of evaluation of COX-2 performance as a diagnostic and prognostic marker of cutaneous melanoma.

The COX-2/PGE2 pathway suppresses apical elimination of RasV12-transformed cells from epithelia

At the initial stage of carcinogenesis, when RasV12-transformed cells are surrounded by normal epithelial cells, RasV12 cells are apically extruded from epithelia through cell competition with the surrounding normal cells. In this study, we demonstrate that expression of cyclooxygenase (COX)-2 is upregulated in normal cells surrounding RasV12-transformed cells. Addition of COX inhibitor or COX-2-knockout promotes apical extrusion of RasV12 cells. Furthermore, production of Prostaglandin (PG) E2, a downstream prostanoid of COX-2, is elevated in normal cells surrounding RasV12 cells, and addition of PGE2 suppresses apical extrusion of RasV12 cells. In a cell competition mouse model, expression of COX-2 is elevated in pancreatic epithelia harbouring RasV12-exressing cells, and the COX inhibitor ibuprofen promotes apical extrusion of RasV12 cells. Moreover, caerulein-induced chronic inflammation substantially suppresses apical elimination of RasV12 cells. These results indicate that intrinsically or extrinsically mediated inflammation can promote tumour initiation by diminishing cell competition between normal and transformed cells.

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.

Selenium and selenoproteins in prostanoid metabolism and immunity

Selenium (Se) is an essential trace element that functions in the form of the 21st amino acid, selenocysteine (Sec) in a defined set of proteins. Se deficiency is associated with pathological conditions in humans and animals, where incorporation of Sec into selenoproteins is reduced along with their expression and catalytic activity. Supplementation of Se-deficient population with Se has shown health benefits suggesting the importance of Se in physiology. An interesting paradigm to explain, in part, the health benefits of Se stems from the observations that selenoprotein-dependent modulation of inflammation and efficient resolution of inflammation relies on mechanisms involving a group of bioactive lipid mediators, prostanoids, which orchestrate a concerted action toward maintenance and restoration of homeostatic immune responses. Such an effect involves the interaction of various immune cells with these lipid mediators where cellular redox gatekeeper functions of selenoproteins further aid in not only dampening inflammation, but also initiating an effective and active resolution process. Here we have summarized the current literature on the multifaceted roles of Se/selenoproteins in the regulation of these bioactive lipid mediators and their immunomodulatory effects.

Cannabidiol and Cannabinoid Compounds as Potential Strategies for Treating Parkinson's Disease and L-DOPA-Induced Dyskinesia

Parkinson's disease (PD) and L-DOPA-induced dyskinesia (LID) are motor disorders with significant impact on the patient's quality of life. Unfortunately, pharmacological treatments that improve these disorders without causing severe side effects are not yet available. Delay in initiating L-DOPA is no longer recommended as LID development is a function of disease duration rather than cumulative L-DOPA exposure. Manipulation of the endocannabinoid system could be a promising therapy to control PD and LID symptoms. In this way, phytocannabinoids and synthetic cannabinoids, such as cannabidiol (CBD), the principal non-psychotomimetic constituent of the Cannabis sativa plant, have received considerable attention in the last decade. In this review, we present clinical and preclinical evidence suggesting CBD and other cannabinoids have therapeutic effects in PD and LID. Here, we discuss CBD pharmacology, as well as its neuroprotective effects and those of other cannabinoids. Finally, we discuss the modulation of several pro- or anti-inflammatory factors as possible mechanisms responsible for the therapeutic/neuroprotective potential of Cannabis-derived/cannabinoid synthetic compounds in motor disorders.

T cell-derived soluble glycoprotein GPIbα mediates PGE2 production in human monocytes activated with the vaccine adjuvant MDP

Vaccine adjuvants containing analogs of microbial products activate pattern recognition receptors (PRRs) on antigen-presenting cells, including monocytes and macrophages, which can cause prostaglandin E₂ (PGE₂) release and consequently undesired inflammatory responses and fever in vaccine recipients. Here, we studied the mechanism of PGE₂ production by human monocytes activated with muramyl dipeptide (MDP) adjuvant, which activates cytosolic nucleotide-binding oligomerization domain 2 (NOD2). In rabbits, administration of MDP elicited an early increase in PGE₂ followed by fever. In human monocytes, MDP alone did not induce PGE₂ production. However, high amounts of PGE₂ and the proinflammatory cytokines IL-1β and IL-6 were secreted by monocytes activated with MDP in the presence of conditioned medium obtained from CD3 bead-isolated T cells (Tc CM) but not from those isolated without CD3 beads. Mass spectrometry and immunoblotting revealed that the costimulatory factor in Tc CM was glycoprotein Ib α (GPIbα). Antibody-mediated blockade of GPIbα or of its receptor, Mac-1 integrin, inhibited the secretion of PGE₂, IL-1β, and IL-6 in MDP + Tc CM-activated monocytes, whereas recombinant GPIbα protein increased PGE₂ production by MDP-treated monocytes. In vivo, COX2 mRNA abundance was reduced in the liver and spleen of Mac-1 KO mice after administration of MDP compared with that of treated wild-type mice. Our findings suggest that the production of PGE₂ and proinflammatory cytokines by MDP-activated monocytes is mediated by cooperation between two signaling pathways: one delivered by MDP through NOD2 and a second through activation of Mac-1 by T cell-derived GPIbα.

Lycopene Inhibits Activation of Epidermal Growth Factor Receptor and Expression of Cyclooxygenase-2 in Gastric Cancer Cells

Reactive oxygen species (ROS) contribute to the oncogenic phenotype of cancer cells by acting as signaling molecules for inducing proliferation. ROS are known to activate the epidermal growth factor receptor (EGFR), which causes the activation of the Ras/mitogen-activated protein kinases (MAPKs) pathway. The Ras-dependent pathway promotes the activation of nuclear factor-kappa-light-chain-enhancer of activated B cells (NF-κB), a transcriptional modulator of cyclooxygenase-2 (COX-2) that induces cell proliferation. Lycopene is a potent antioxidant carotenoid and is responsible for the red color of fruits and vegetables. This study aims to investigate whether lycopene inhibits proliferation and induces apoptosis in gastric cancer AGS cells by suppressing the EGFR/Ras/MAPK and NF-κB-COX-2 signaling axis. Lycopene decreased cell viability and increased apoptotic indices (DNA fragmentation, apoptosis inducing factor, cleavage of caspase-3 and caspase-9, Bax/Bcl-2 ratio). Lycopene reduced the level of intracellular and mitochondrial ROS and decreased the activation of the ROS-mediated EGFR/Ras/extracellular signal-regulated kinase (ERK) and p38 MAPK pathways, thus leading to attenuation of the DNA-binding activity of NF-κB p50/p50 and the level of COX-2 gene expression. These results show that lycopene-induced apoptosis and inhibition of proliferation occur via inhibition of ROS-activated EGFR/Ras/ERK and p38 MAPK pathways and NF-κB-mediated COX-2 gene expression in AGS cells. In conclusion, consumption of lycopene-enriched foods could decrease the incidence of gastric cancer.

Association of COX2 -765G>C promoter polymorphism and coronary artery disease in Korean population

BACKGROUND

Cyclooxygenase-2 (COX2) plays a role in the formation of prostaglandins, which contribute to the inflammation involved in atherosclerosis. However, the role of the COX2 -765G>C polymorphism in susceptibility to coronary artery disease (CAD) is controversial.

OBJECTIVE

To identify the association between COX2 -765G>C polymorphism with CAD risk in Korean patients. We recruited 622 patients who were diagnosed to have coronary artery disease and 202 controls who did not have history and vascular disease risk factors.

METHODS

Using polymerase chain reaction-restriction fragment length polymorphism, the COX2 -765G>C polymorphism was analyzed in 622 Korean patients who received percutaneous coronary intervention and in 202 healthy control subjects.

RESULTS

The GC+CC genotype frequencies of the -765G>C polymorphism were significantly different between the CAD and control groups. The COX2 -765G>C polymorphism showed peculiar associations with CAD according to the presence of hyperlipidemia and plasma folate levels. However, there were no associations between the -765G>C polymorphism and the rates of hypertension, diabetes mellitus, or homocysteine levels.

CONCLUSION

This study suggests that the COX2 -765G>C polymorphism is a possible genetic determinant for the risk of CAD, and an individual risk factor in Koreans. Thus, further association studies between the COX2 polymorphism and atherosclerotic-related diseases such as cerebrovascular or cardiovascular diseases in other races or ethnicities will be needed.

A Review of the Actions of Endogenous and Exogenous Vasoactive Substances during the Estrous Cycle and Pregnancy in Rats

Vascular endothelium plays a key role in regulating cardiovascular homeostasis by controlling the vascular tone. Variations in sex hormones during the reproductive cycle of females affect the homeostasis of the cardiovascular system. Also, the evidence shows that estrogens show a cardioprotective effect. On this basis, this study describes some vascular responses induced by vasoactive substances during the estrous cycle in rats. We obtained the information available on this topic from the online databases that included scientific articles published in the Web of Science, PubMed, and Scielo. Many investigations have evaluated the vasoactive response of substances such as acetylcholine and norepinephrine during the estrous cycle. In this review, we specifically described the vascular response to vasoactive substances in rats during the estrous cycle, pregnancy, and in ovariectomized rats. In addition, we discussed the existence of different signaling pathways that modulate vascular function. The knowledge of these effects is relevant for the optimization and development of new treatments for some vascular pathologies.

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.

Oncogenic Activation of Nrf2, Though as a Master Antioxidant Transcription Factor, Liberated by Specific Knockout of the Full-Length Nrf1α that Acts as a Dominant Tumor Repressor

Liver-specific knockout of Nrf1 in the mouse leads to spontaneous development of non- alcoholic steatohepatitis with dyslipidemia, and then its deterioration results in hepatoma, but the underlying mechanism remains elusive to date. A similar pathological model is reconstructed here by using human Nrf1α-specific knockout cell lines. Our evidence has demonstrated that a marked increase of the inflammation marker COX2 definitely occurs in Nrf1α^−/− cells. Loss of Nrf1α leads to hyperactivation of Nrf2, which results from substantial decreases in Keap1, PTEN and most of 26S proteasomal subunits in Nrf1α^−/− cells. Further investigation of xenograft model mice showed that malignant growth of Nrf1α^−/−-derived tumors is almost abolished by silencing of Nrf2, while Nrf1α^+/+-tumor is markedly repressed by an inactive mutant (i.e., Nrf2^−/−ΔTA), but largely unaffected by a priori constitutive activator (i.e., caNrf2^ΔN). Mechanistic studies, combined with transcriptomic sequencing, unraveled a panoramic view of opposing and unifying inter-regulatory cross-talks between Nrf1α and Nrf2 at different layers of the endogenous regulatory networks from multiple signaling towards differential expression profiling of target genes. Collectively, Nrf1α manifests a dominant tumor-suppressive effect by confining Nrf2 oncogenicity. Though as a tumor promoter, Nrf2 can also, in turn, directly activate the transcriptional expression of Nrf1 to form a negative feedback loop. In view of such mutual inter-regulation by between Nrf1α and Nrf2, it should thus be taken severe cautions to interpret the experimental results from loss of Nrf1α, Nrf2 or both.

Antiemetic doses of dexamethasone and their effects on immune cell populations and plasma mediators of inflammation resolution in healthy volunteers

INTRODUCTION

The synthetic glucocorticoid dexamethasone is a commonly administered antiemetic. It has immunosuppressive effects and may alter postoperative blood glucose concentrations. Dexamethasone can effect key enzymes involved in inflammation resolution that is an active process driven by specialised lipid mediators of inflammation resolution (SPM). The purpose of this study in healthy volunteers was to examine whether dexamethasone effects cell populations and synthesis of SPM that are critical for the resolution of inflammation.

METHODS

Thirty-two healthy volunteers were randomly allocated to receive saline (Control) or dexamethasone 2 mg, 4 mg or 8 mg intravenously. Venous blood samples were collected at baseline before administration of treatment, and at 4 h, 24 h and one-week post-treatment. At each time point, measurements included blood glucose and macrophage migration inhibition factor (MMIF), full blood count including lymphocyte subsets, monocytes, neutrophils, eosinophils and basophils by flow cytometry, and plasma SPM using liquid chromatography tandem mass spectrometry. The effect of dexamethasone dose and time on all measures was analysed using linear mixed models.

RESULTS

There was a dose-dependent increase in neutrophil count after dexamethasone that persisted for 24 h. In contrast, there was a dose-dependent reduction in counts of monocytes, lymphocytes, basophils and eosinophils 4 h after dexamethasone, followed by a rebound increase in cell counts at 24 h. Seven days after administration of dexamethasone, all cell counts were similar to baseline levels. MMIF concentration, glucose and natural killer cell counts were not significantly affected by dexamethasone. There was a significant gender effect on plasma SPM such that levels of 17-HDHA, RvD1, 17R-RvD1 and RvE2 in females were on average 14%-50% lower than males. In a linear mixed model that adjusted for neutrophil count, there was a significant interaction between the dose of dexamethasone and time, on plasma 17R-RvD1 such that plasma 17R-RvD1 fell in a dose-dependent manner until 4 h after administration of dexamethasone. There were no significant effects of dexamethasone on the other plasma SPM (18-HEPE, RvE2, 17-HDHA, RvD1, RvD2 and 14-HDHA) measured.

DISCUSSION

This is the first study in healthy volunteers to demonstrate that commonly employed antiemetic doses of dexamethasone affect immune cell populations and plasma levels of 17R-RvD1 an SPM with anti-nociceptive properties. If similar changes occur in surgical patients, then this may have implications for acute infection risk in the post-operative period.

Expression and Molecular Regulation of the Cox2 Gene in Gastroenteropancreatic Neuroendocrine Tumors and Antiproliferation of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

Background

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has had a significant increase over the past 4 decades. The pathophysiological role of the cyclooxygenase-2 (cox-2) gene and factors responsible for the expression in GEP-NETs is of clinical value. Current study determined the expression of cox-2 gene in human GEP-NET tissues and corresponding cell lines, investigated the molecular mechanisms underlying the regulation of cox-2 gene expression and assessed the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on both anchorage-dependent and independent growth of GEP-NET cells.

Material/Methods

GEP-NET tissues and QGP-1, BON, and LCC-18 GEP-NET cell lines were used. The expression of cox-2 gene was analyzed by immunohistochemistry, western blot, RT-PCR, and enzyme immunoassay. Transient transfection and luciferase assays along with electrophoretic mobility shift assays were conducted to explore the regulation of cox-2 gene expression. The effect of COX-inhibitors on GEP-NET cell growth was determined by proliferation assays and colony growth assessment.

Results

We found 87.8% of GEP-NET tissues stained positive for COX-2. QGP-1 and LCC-18 cells expressed cox-2 gene. PGE2 (prostaglandin E2) amounts quantified in the supernatants of NET cells matched to cox-2 expression level. The CRE-E-box element (−56 to −48 bp) and binding of USF1, USF2, and CREB transcription factors to this proximal promoter element were essential for cox-2 promoter activity in GEP-NET cells. COX-2-specific inhibitor NS-398 potently and dose-dependently inhibited PGE2 release from QGP-1 cells. Interestingly, both NS-398 and acetylic salicylic acid effectively suppressed proliferation of QGP-1 and BON cells in a dose-dependent manner.

Conclusions

The majority of GEP-NETs over express cox-2 gene. The binding of CREB and USF-1/-2 transcription factors to a proximal, overlapping CRE-Ebox element is the underlying mechanism for cox-2 gene expression. NSAIDs potently suppressed the proliferations and may offer a novel approach for chemoprevention and therapy of GEP-NETs.