15-Deoxy-Δ¹²,¹⁴-prostaglandin J₂, an electrophilic lipid mediator of anti-inflammatory and pro-resolving signaling

Potent activity of prostaglandin J2 on prostanoid DP receptors

Prostaglandin D2 (PGD2), an anti-inflammatory mediator, is acting through Gs-protein coupled D-type prostanoid (DP) receptors. DP receptors are not extensively distributed; in tissues, they are the least abundant among members of the prostanoid receptor family, whereas their primary ligand PGD2 is the main prostanoid in most tissues. PGD2 is dehydrated or isomerized to a number of metabolites enzymatically or non-enzymatically. To understand why many metabolites of PGD2 are produced via different pathways, regular cell-based experiments, Black/Leff operational model calculations, and in silico simulations were utilized. Here we show, among the 5 metabolites of PGD2, prostaglandin J2 (PGJ2) was the most potent metabolite for DP receptors, particularly in the cAMP signaling pathway. This result was attributed to PGJ2 forming an extra, and/or stronger hydrogen bond by more negatively charged carbonyl in the cyclopentene ring with DP receptors than PGD2. Therefore, when PGD2 is released into the blood, it would activate DP receptors, which are then continuously activated by PGJ2 to sustain the DP receptor/cAMP-mediated signaling pathway. Thus, the anti-inflammatory effects of PGD2 may be taken over/out competed and/or even enhanced by PGJ2. Here, PGJ2 was found to be a standout mediator of cAMP-mediated signaling pathway, that induces more potent and prolonged DP receptor-activities as a biased ligand, possibly for resolving the inflammatory reaction. Moreover, since each metabolite showed different property, these results provide insight into why many metabolites of PGD2 are produced, and the miscellaneous physiological roles induced by the main prostanoid in most tissues through the least abundant DP receptors.

The Therapeutic Potential of Supersulfides in Oxidative Stress-Related Diseases

Oxidation-reduction (redox) reactions are fundamental to sustaining life, with reactive oxygen and nitrogen species playing pivotal roles in cellular signaling and homeostasis. However, excessive oxidative stress disrupts redox balance, contributing to a wide range of diseases, including inflammatory and pulmonary disorders, neurodegeneration, and cancer. Although numerous antioxidant therapies have been developed and tested for oxidative stress-related diseases, their clinical efficacy remains limited. Here, we introduce the emerging concept of 'supersulfides', a class of redox molecule species with unique antioxidant and nucleophilic properties, which have recently been recognized as crucial regulators of cellular redox homeostasis. Unlike traditional antioxidants, supersulfides offer novel mechanisms of action that directly target the underlying processes of oxidative stress. This review summarizes current knowledge on supersulfides, highlighting their roles in oxidative stress and associated diseases, as well as the mechanisms underlying oxidative stress-related pathology. The therapeutic potential of synthetic supersulfides for treating oxidative stress-related diseases is also discussed. A comprehensive understanding of the molecular and cellular basis of redox biology can help to guide the development of innovative redox-based therapeutic strategies aimed at preventing and treating diseases associated with disturbed redox regulation.

Atopic dermatitis treatment: A comprehensive review of conventional and novel bioengineered approaches

Atopic dermatitis (AD) remains a challenging condition, with conventional treatments often leading to adverse effects and limited efficacy. This review explores the diverse landscape of AD treatments, encompassing conventional methods, novel topical and systemic therapies, and emerging bioengineered strategies. While conventional drug administration often requires high dosages or frequent administration, leading to adverse effects, targeted biologics have shown promise. Phototherapy and wet wrap therapy, while helpful, have limitations. Given these factors, the need for modern and effective therapeutic strategies for AD is pressing. Complementary or alternative therapies have garnered significant attention in recent years as a compelling treatment for AD. Among these, functionalized biomaterials and textiles with physicochemical, nanotechnology-based characteristics, or bioengineered features are some of the most common typical adjuvant therapies. The multifunctional-engineered biomaterials, as a new generation of biomedical materials, and stem cells, seem to hold tremendous promise for the treatment of dermatological diseases like AD. Biomaterials have seen great success, especially in various medical fields, due to their unique and adaptable characteristics. These materials, including collagen, PCL, and PLGA, offer unique advantages, such as biocompatibility, biodegradability, controlled drug release, and enhanced drug retention.

Identification of CRTH2 as a New PPARγ-Target Gene in T Cells Suggested CRTH2 Dependent Conversion of Th2 Cells as Therapeutic Concept in COVID-19 Infection

Background

COVID-19 is a serious viral infection, which is often associated with a lethal outcome. Therefore, understanding mechanisms, which affect the immune response during SARS-CoV2 infection, are important.

Methods

To address this, we determined the number of T cells in peripheral blood derived from intensive care COVID-19 patients. Based on our previous studies, evaluating PPARγ-dependent T cell apoptosis in sepsis patients, we monitored PPARγ expression. We performed a next generation sequencing approach to identify putative PPARγ-target genes in Jurkat T cells and used a PPARγ transactivation assay in HEK293T cells. Finally, we translated these data to primary T cells derived from healthy donors.

Results

A significantly reduced count of total CD3+ T lymphocytes and the CD4+ and CD8+ subpopulations was observed. Also, the numbers of anti-inflammatory, resolutive Th2 cells and FoxP3-positive regulatory T cells (Treg) were decreased. We observed an augmented PPARγ expression in CD4+ T cells of intensive care COVID-19 patients. Adapted from a next generation sequencing approach in Jurkat T cells, we found the chemoattractant receptor-homologous molecule expressed on T helper type 2 cells (CRTH2) as one gene regulated by PPARγ in T cells. This Th2 marker is a receptor for prostaglandin D and its metabolic degradation product 15-deoxy-∆12,14-prostaglandin J2 (15d-PGJ2), an established endogenous PPARγ agonist. In line, we observed an increased PPARγ transactivation in response to 15d-PGJ2 treatment in HEK293T cells overexpressing CRTH2. Translating these data to primary T cells, we found that Th2 differentiation was associated with an increased expression of CRTH2. Interestingly, these CRTH2+ T cells were prone to apoptosis.

Conclusion

These mechanistic data suggest an involvement of PPARγ in Th2 differentiation and T cell depletion in COVID-19 patients.

Targeting cyclooxygenase-2 for chemoprevention of inflammation-associated intestinal carcinogenesis: An update

Mounting evidence from preclinical and clinical studies suggests that persistent inflammation functions as a driving force in the journey to cancer. Cyclooxygenase-2 (COX-2) is a key enzyme involved in inflammatory signaling. While being transiently upregulated upon inflammatory stimuli, COX-2 has been found to be consistently overexpressed in human colorectal cancer and several other malignancies. The association between chronic inflammation and cancer has been revisited: cancer can arise when inflammation fails to resolve. Besides its proinflammatory functions, COX-2 also catalyzes the production of pro-resolving as well as anti-inflammatory metabolites from polyunsaturated fatty acids. This may account for the side effects caused by long term use of some COX-2 inhibitory drugs during the cancer chemopreventive trials. This review summarizes the latest findings highlighting the dual functions of COX-2 in the context of its implications in the development, maintenance, and progression of cancer.

New aspects of redox signaling mediated by supersulfides in health and disease

Oxygen molecules accept electrons from the respiratory chain in the mitochondria and are responsible for energy production in aerobic organisms. The reactive oxygen species formed via these oxygen reduction processes undergo complicated electron transfer reactions with other biological substances, which leads to alterations in their physiological functions and cause diverse biological and pathophysiological consequences (e.g., oxidative stress). Oxygen accounts for only a small proportion of the redox reactions in organisms, especially under aerobic or hypoxic conditions but not under anaerobic and hypoxic conditions. This article discusses a completely new concept of redox biology, which is governed by redox-active supersulfides, i.e., sulfur-catenated molecular species. These species are present in abundance in all organisms but remain largely unexplored in terms of redox biology and life science research. In fact, accumulating evidence shows that supersulfides have extensive redox chemical properties and that they can be readily ionized or radicalized to participate in energy metabolism, redox signaling, and oxidative stress responses in cells and in vivo. Thus, pharmacological intervention and medicinal modulation of supersulfide activities have been shown to benefit the regulation of disease pathogenesis as well as disease control.

Redox Regulation of Xenobiotics by Reactive Sulfur and Supersulfide Species

Significance: Routine exposure to xenobiotics is unavoidable during our lifetimes. Certain xenobiotics are hazardous to human health, and are metabolized in the body to render them less toxic. During this process, several detoxification enzymes cooperatively metabolize xenobiotics. Glutathione (GSH) conjugation plays an important role in the metabolism of electrophilic xenobiotics. Recent Advances: Recent advances in reactive sulfur and supersulfide (RSS) analyses showed that persulfides and polysulfides bound to low-molecular-weight thiols, such as GSH, and to protein thiols are abundant in both eukaryotes and prokaryotes. The highly nucleophilic nature of hydropersulfides and hydropolysulfides contributes to cell protection against oxidative stress and electrophilic stress. Critical Issues: In contrast to GSH conjugation to electrophiles that is aided by glutathione S-transferase (GST), persulfides and polysulfides can directly form conjugates with electrophiles without the catalytic actions of GST. The polysulfur bonds in the conjugates are further reduced by perthioanions and polythioanions derived from RSS to form sulfhydrated metabolites that are no longer electrophilic but rather nucleophilic, and differ from metabolites that are formed via GSH conjugation. Future Directions: In view of the abundance of RSS in cells and tissues, metabolism of xenobiotics that is mediated by RSS warrants additional investigations, such as studies of the impact of microbiota-derived RSS on xenobiotic metabolism. Metabolites formed from reactions between electrophiles and RSS may be potential biomarkers for monitoring exposure to electrophiles and for studying their metabolism by RSS. Antioxid. Redox Signal. 40, 679-690.

A new type of sulfation reaction: C-sulfonation for α,β-unsaturated carbonyl groups by a novel sulfotransferase SULT7A1

Cytosolic sulfotransferases (SULTs) are cytosolic enzymes that catalyze the transfer of sulfonate group to key endogenous compounds, altering the physiological functions of their substrates. SULT enzymes catalyze the O-sulfonation of hydroxy groups or N-sulfonation of amino groups of substrate compounds. In this study, we report the discovery of C-sulfonation of α,β-unsaturated carbonyl groups mediated by a new SULT enzyme, SULT7A1, and human SULT1C4. Enzymatic assays revealed that SULT7A1 is capable of transferring the sulfonate group from 3'-phosphoadenosine 5'-phosphosulfate to the α-carbon of α,β-unsaturated carbonyl-containing compounds, including cyclopentenone prostaglandins as representative endogenous substrates. Structural analyses of SULT7A1 suggest that the C-sulfonation reaction is catalyzed by a novel mechanism mediated by His and Cys residues in the active site. Ligand-activity assays demonstrated that sulfonated 15-deoxy prostaglandin J2 exhibits antagonist activity against the prostaglandin receptor EP2 and the prostacyclin receptor IP. Modification of α,β-unsaturated carbonyl groups via the new prostaglandin-sulfonating enzyme, SULT7A1, may regulate the physiological function of prostaglandins in the gut. Discovery of C-sulfonation of α,β-unsaturated carbonyl groups will broaden the spectrum of potential substrates and physiological functions of SULTs.

Metabolic characteristics of voriconazole - Induced liver injury in rats

Voriconazole (VOR) - induced liver injury is a common adverse reaction, and can lead to serious clinical outcomes. It is of great significance to describe the metabolic characteristics of VOR - induced liver injury and to elucidate the potential mechanisms. This study investigated the changes of plasma metabolic profiles in a rat model of VOR - induced liver injury by non - targeted metabolomics. Correlation analysis was performed between differentially expressed metabolites and plasma liver function indexes. The metabolites with strong correlation were determined for their predictive performance for liver injury using receiver operating characteristic (ROC) curve analysis. Potential biomarkers were then screened combined with liver pathological scores. Finally, the expression level of genes that involved in lipid metabolism were determined in rat liver to verify the mechanism of VOR - induced liver injury we proposed. VOR - induced liver injury in rats was characterized by plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) elevation, the lipid droplets accumulation in liver, as well as inflammation and fibrosis. Significant changes of plasma metabolites were observed, with a decrease in lipid metabolites accounting for over 50% of all changed metabolites, and alterations of cholesterol and bile acids metabolites. The decrease of 3 phosphatidylcholine (PC) in plasma could indicate the occurrence of VOR - induced liver injury. Decreased fatty acids (FA) oxidation and bile acid excretion might be the potential mechanisms of VOR - induced liver injury. This study provided new insights into the molecular characterization of VOR - induced liver injury.

Association between insulin and Nrf2 signalling pathway in Alzheimer's disease: A molecular landscape

Insulin, a well-known hormone, has been implicated as a regulator of blood glucose levels for almost a century now. Over the past few decades, the non-glycemic actions of insulin i.e. neuronal growth and proliferation have been extensively studied. In 2005, Dr. Suzanne de La Monte and her team reported that insulin might be involved in the pathogenesis of Alzheimer's Disease (AD) and thus coined a term "Type-3 diabetes" This hypothesis was supported by several subsequent studies. The nuclear factor erythroid 2- related factor 2 (Nrf2) triggers a cascade of events under the regulation of distinct mechanisms including protein stability, phosphorylation and nuclear cytoplasmic shuttling, finally leading to the protection against oxidative damage. The Nrf2 pathway has been investigated extensively in relevance to neurodegenerative disorders, particularly AD. Many studies have indicated a strong correlation between insulin and Nrf2 signalling pathways both in the periphery and the brainbut merely few of them have focused on elucidating their inter-connective role in AD. The present review emphasizes key molecular pathways that correlate the role of insulin with Nrf2 during AD. The review has also identified key unexplored areas that could be investigated in future to further establish the insulin and Nrf2 influence in AD.

Endocannabinoid 2-Arachidonoylglycerol Synthesis and Metabolism at Neuronal Nuclear Matrix Fractions Derived from Adult Rat Brain Cortex

In this report, we describe the kinetics characteristics of the diacylglycerol lipase-α (DGLα) located at the nuclear matrix of nuclei derived from adult cortical neurons. Thus, using high-resolution fluorescence microscopy, classical biochemical subcellular fractionation, and Western blot techniques, we demonstrate that the DGLα enzyme is located in the matrix of neuronal nuclei. Furthermore, by quantifying the 2-arachidonoylglycerol (2-AG) level by liquid chromatography and mass spectrometry when 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG) was exogenously added as substrate, we describe the presence of a mechanism for 2-AG production through DGLα dependent biosynthesis with an apparent K_m (K_m^app) of 180 µM and a V_max of 1.3 pmol min^-1 µg^-1 protein. We also examined the presence of enzymes with hydrolytic and oxygenase activities that are able to use 2-AG as substrate, and described the localization and compartmentalization of the major 2-AG degradation enzymes, namely monoacylglycerol lipase (MGL), fatty acid amide hydrolase (FAAH), α/β-hydrolase domain 12 protein (ABHD12) and cyclooxygenase-2 (COX2). Of these, only ABHD12 exhibited the same distribution with respect to chromatin, lamin B1, SC-35 and NeuN as that described for DGLα. When 2-AG was exogenously added, we observed the production of arachidonic acid (AA), which was prevented by inhibitors (but not specific MGL or ABHD6 inhibitors) of the ABHD family. Overall, our results expand knowledge about the subcellular distribution of neuronal DGLα, and provide biochemical and morphological evidence to ensure that 2-AG is produced in the neuronal nuclear matrix. Thus, this work paves the way for proposing a working hypothesis about the role of 2-AG produced in neuronal nuclei.

Peroxisome proliferator-activated receptor-gamma (PPARγ) and its immunomodulation function: current understanding and future therapeutic implications

INTRODUCTION

: Pain is a multidimensional experience involving the biological, psychological, and social dimensions of each individual. Particularly, the biological aspects of pain conditions are a response of the neuroimmunology system and the control of painful conditions is a worldwide challenge for researchers. Although years of investigation on pain experience and treatment exist, the high prevalence of chronic pain is still a fact.

AREAS COVERED

: Peroxisome proliferator-activated receptor-gamma (PPARγ) is a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily. It regulates several metabolic pathways, including lipid biosynthesis and glucose metabolism, when activated. However, PPARγ activation also has a critical immunomodulatory and neuroprotective effect.

EXPERT OPINION

: This review summarizes the evidence of synthetic or natural PPARγ ligands such as 15d-PGJ₂, epoxyeicosatrienoic acids, thiazolidinediones, and specialized pro-resolving mediators, representing an interesting therapeutic tool for pain control.

15-Deoxy-Delta-12,14-prostaglandin J2 modulates pro-labour and pro-inflammatory responses in human myocytes, vaginal and amnion epithelial cells

BACKGROUND

Prematurity is the leading cause of childhood death under the age of five. The aetiology of preterm birth is multifactorial; however, inflammation and infection are the most common causal factors, supporting a potential role for immunomodulation as a therapeutic strategy. 15-Deoxy-Delta-12,14-prostaglandin J2 (15dPGJ2) is an anti-inflammatory prostaglandin and has been shown to delay lipopolysaccharide (LPS) induced preterm labour in mice and improve pup survival. This study explores the immunomodulatory effect of 15dPGJ2 on the transcription factors NF-κB and AP-1, pro-inflammatory cytokines, and contraction associated proteins in human cultured myocytes, vaginal epithelial cell line (VECs) and primary amnion epithelial cells (AECs).

METHODS

Cells were pre-incubated with 32µM of 15dPGJ2 and stimulated with 1ng/mL of IL-1β as an in vitro model of inflammation. Western immunoblotting was used to detect phosphorylated p-65 and phosphorylated c-Jun as markers of NF-κB and AP-1 activation, respectively. mRNA expression of the pro-inflammatory cytokines IL-6, IL-8, and TNF-α was examined, and protein expression of COX-2 and PGE2 were detected by western immunoblotting and ELISA respectively. Myometrial contractility was examined ex-vivo using a myograph.

RESULTS

15dPGJ2 inhibited IL-1β-induced activation of NF-κB and AP-1, and expression of IL-6, IL-8, TNF-α, COX-2 and PGE2 in myocytes, with no effect on myometrial contractility or cell viability. Despite inhibiting IL-1β-induced activation of NF-κB, expression of IL-6, TNF-α, and COX-2, 15dPGJ2 led to activation of AP-1, increased production of PGE2 and increased cell death in VECs and AECs.

CONCLUSION

We conclude that 15dPGJ2 has differential effects on inflammatory modulation depending on cell type and is therefore unlikely to be a useful therapeutic agent for the prevention of preterm birth.

Resolution of inflammation in bone regeneration: From understandings to therapeutic applications

Impaired bone healing occurs in 5-10% of cases following injury, leading to a significant economic and clinical impact. While an inflammatory response upon injury is necessary to facilitate healing, its resolution is critical for bone tissue repair as elevated acute or chronic inflammation is associated with impaired healing in patients and animal models. This process is governed by important crosstalk between immune cells through mediators that contribute to resolution of inflammation in the local healing environment. Approaches modulating the initial inflammatory phase followed by its resolution leads to a pro-regenerative environment for bone regeneration. In this review, we discuss the role of inflammation in bone repair, the negative impact of dysregulated inflammation on bone tissue regeneration, and how timely resolution of inflammation is necessary to achieve normal healing. We will discuss applications of biomaterials to treat large bone defects with a specific focus on resolution of inflammation to modulate the immune environment following bone injury, and their observed functional benefits. We conclude the review by discussing future strategies that could lead to the realization of anti-inflammatory therapeutics for bone tissue repair.

Roles of Eicosanoids in Regulating Inflammation and Neutrophil Migration as an Innate Host Response to Bacterial Infections

Eicosanoids are lipid-based signaling molecules that play a unique role in innate immune responses. The multiple types of eicosanoids, such as prostaglandins (PGs) and leukotrienes (LTs), allow the innate immune cells to respond rapidly to bacterial invaders. Bacterial pathogens alter cyclooxygenase (COX)-derived prostaglandins (PGs) in macrophages, such as PGE2 15d-PGJ₂, and lipoxygenase (LOX)-derived leukotriene LTB_4, which has chemotactic functions. The PG synthesis and secretion are regulated by substrate availability of arachidonic acid and by the COX-2 enzyme, and the expression of this protein is regulated at multiple levels, both transcriptionally and posttranscriptionally. Bacterial pathogens use virulence strategies such as type three secretion systems (T3SSs) to deliver virulence factors altering the expression of eicosanoid-specific biosynthetic enzymes, thereby modulating the host response to bacterial lipopolysaccharides (LPS). Recent advances have identified a novel role of eicosanoids in inflammasome activation during intracellular infection with bacterial pathogens. Specifically, PGE₂ was found to enhance inflammasome activation, driving the formation of pore-induced intracellular traps (PITs), thus trapping bacteria from escaping the dying cell. Finally, eicosanoids and IL-1β released from macrophages are implicated in the efferocytosis of neighboring neutrophils. Neutrophils play an essential role in phagocytosing and degrading PITs and associated bacteria to restore homeostasis. This review focuses on the novel functions of host-derived eicosanoids in the host-pathogen interactions.

Prostanoids and Resolution of Inflammation - Beyond the Lipid-Mediator Class Switch

Bioactive lipid mediators play a major role in regulating inflammatory processes. Herein, early pro-inflammatory phases are characterized and regulated by prostanoids and leukotrienes, whereas specialized pro-resolving mediators (SPM), including lipoxins, resolvins, protectins, and maresins, dominate during the resolution phase. While pro-inflammatory properties of prostanoids have been studied extensively, their impact on later phases of the inflammatory process has been attributed mainly to their ability to initiate the lipid-mediator class switch towards SPM. Yet, there is accumulating evidence that prostanoids directly contribute to the resolution of inflammation and return to homeostasis. In this mini review, we summarize the current knowledge of the resolution-regulatory properties of prostanoids and discuss potential implications for anti-inflammatory, prostanoid-targeted therapeutic interventions.

Nitric Oxide and Electrophilic Cyclopentenone Prostaglandins in Redox signaling, Regulation of Cytoskeleton Dynamics and Intercellular Communication

Nitric oxide (NO) and electrophilic cyclopentenone prostaglandins (CyPG) are local mediators that modulate cellular response to oxidative stress in different pathophysiological processes. In particular, there is increasing evidence about their functional role during inflammation and immune responses. Although the mechanistic details about their relationship and functional interactions are still far from resolved, NO and CyPG share the ability to promote redox-based post-translational modification (PTM) of proteins that play key roles in cellular homeostasis, signal transduction and transcription. NO-induced S-nitrosylation and S-glutathionylation as well as cyclopentenone-mediated adduct formation, are a few of the main PTMs by which intra- and inter-cellular signaling are regulated. There is a growing body of evidence indicating that actin and actin-binding proteins are susceptible to covalent PTM by these agents. It is well known that the actin cytoskeleton is key for the establishment of interactions among leukocytes, endothelial and muscle cells, enabling cellular activation and migration. In this review we analyze the current knowledge about the actions exerted by NO and CyPG electrophilic lipids on the regulation of actin dynamics and cytoskeleton organization, and discuss some open questions regarding their functional relevance in the regulation of intercellular communication.

Fa(c)t checking: How fatty acids shape metabolism and function of macrophages and dendritic cells

In recent years there have been major advances in our understanding of the role of free fatty acids (FAs) and their metabolism in shaping the functional properties of macrophages and DCs. This review presents the most recent insights into how cell intrinsic FA metabolism controls DC and macrophage function, as well as the current evidence of the importance of various exogenous FAs (such as polyunsaturated FAs and their oxidation products—prostaglandins, leukotrienes, and proresolving lipid mediators) in affecting DC and macrophage biology, by modulating their metabolic properties. Finally, we explore whether targeted modulation of FA metabolism of myeloid cells to steer their function could hold promise in therapeutic settings.

15-Deoxy-Δ12,14-prostaglandin J2 Upregulates VEGF Expression via NRF2 and Heme Oxygenase-1 in Human Breast Cancer Cells

There is a plethora of evidence to support that inflammation is causally linked to carcinogenesis. Cyclooxygenase-2 (COX-2), a rate-limiting enzyme in the biosynthesis of prostaglandins, is inappropriately overexpressed in various cancers and hence recognized as one of the hallmarks of chronic inflammation-associated malignancies. However, the mechanistic role of COX-2 as a link between inflammation and cancer remains largely undefined. In this study, we found that 15-deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂), one of the final products of COX-2, induced upregulation of vascular endothelial growth factor (VEGF) and capillary formation and migration through nuclear factor erythroid 2-related factor 2 (NRF2)-dependent heme oxygenase-1 (HO-1) induction in MCF-7 cells. Analysis of the publicly available TCGA data set showed that high mRNA levels of both COX-2 and NRF2 correlated with the poor clinical outcomes in breast cancer patients. Moreover, human tissue analysis showed that the levels of 15d-PGJ₂ as well the expression of COX-2, NRF2, and HO-1 were found to be increased in human breast cancer tissues. In conclusion, the elevated levels of 15d-PGJ₂ during inflammatory response activate VEGF expression through NRF2-driven induction of HO-1 in human breast cancer cells, proposing a novel mechanism underlying the oncogenic function of 15d-PGJ₂.

Oral administration of curcumin ameliorates pulmonary fibrosis in mice through 15d-PGJ2-mediated induction of hepatocyte growth factor in the colon

Oral administration of curcumin has been shown to inhibit pulmonary fibrosis (PF) despite its extremely low bioavailability. In this study, we investigated the mechanisms underlying the anti-PF effect of curcumin in focus on intestinal endocrine. In bleomycin- and SiO₂-treated mice, curcumin (75, 150 mg· kg^-1 per day) exerted dose-dependent anti-PF effect when administered orally or rectally but not intravenously, implying an intestinal route was involved in the action of curcumin. We speculated that curcumin might promote the generation of gut-derived factors and the latter acted as a mediator subsequently entering the lungs to ameliorate fibrosis. We showed that oral administration of curcumin indeed significantly increased the expression of gut-derived hepatocyte growth factor (HGF) in colon tissues. Furthermore, in bleomycin-treated mice, the upregulated protein level of HGF in lungs by oral curcumin was highly correlated with its anti-PF effect, which was further confirmed by coadministration of c-Met inhibitor SU11274. Curcumin (5-40 μM) dose-dependently increased HGF expression in primary mouse fibroblasts, macrophages, CCD-18Co cells (fibroblast cell line), and RAW264.7 cells (monocyte-macrophage cell line), but not in primary colonic epithelial cells. In CCD-18Co cells and RAW264.7 cells, curcumin dose-dependently activated PPARγ and CREB, whereas PPARγ antagonist GW9662 (1 μM) or cAMP response element (CREB) inhibitor KG-501 (10 μM) significantly decreased the boosting effect of curcumin on HGF expression. Finally, we revealed that curcumin dose-dependently increased the production of 15-deoxy-Δ^{12, 14}-prostaglandin J2 (15d-PGJ2) in CCD-18Co cells and RAW264.7 cells, which was a common upstream of the two transcription factors. Moreover, both the in vitro and in vivo effects of curcumin were diminished by coadministration of HPGDS-inhibitor-1, an inhibitor of 15d-PGJ2 generation. Together, curcumin promotes the expression of HGF in colonic fibroblasts and macrophages by activating PPARγ and CREB via an induction of 15d-PGJ2, and the HGF enters the lungs giving rise to an anti-PF effect.

Could Arachidonic Acid-Derived Pro-Resolving Mediators Be a New Therapeutic Strategy for Asthma Therapy?

Asthma represents one of the leading chronic diseases worldwide and causes a high global burden of death and disability. In asthmatic patients, the exacerbation and chronification of the inflammatory response are often related to a failure in the resolution phase of inflammation. We reviewed the role of the main arachidonic acid (AA) specialized pro-resolving mediators (SPMs) in the resolution of chronic lung inflammation of asthmatics. AA is metabolized by two classes of enzymes, cyclooxygenases (COX), which produce prostaglandins (PGs) and thromboxanes, and lypoxygenases (LOX), which form leukotrienes and lipoxins (LXs). In asthma, two primary pro-resolving derived mediators from COXs are PGE₂ and the cyclopentenone prostaglandin15-Deoxy-Delta-12,14-PGJ₂ (15d-PGJ₂) while from LOXs are the LXA₄ and LXB₄. In different models of asthma, PGE₂, 15d-PGJ₂, and LXs reduced lung inflammation and remodeling. Furthermore, these SPMs inhibited chemotaxis and function of several inflammatory cells involved in asthma pathogenesis, such as eosinophils, and presented an antiremodeling effect in airway epithelial, smooth muscle cells and fibroblasts in vitro. In addition, PGE₂, 15d-PGJ₂, and LXs are all able to induce macrophage reprogramming to an alternative M2 pro-resolving phenotype in vitro and in vivo. Although PGE₂ and LXA₄ showed some beneficial effects in asthmatic patients, there are limitations to their clinical use, since PGE₂ caused side effects, while LXA₄ presented low stability. Therefore, despite the strong evidence that these AA-derived SPMs induce resolution of both inflammatory response and tissue remodeling in asthma, safer and more stable analogs must be developed for further clinical investigation of their application in asthma treatment.

15-Deoxy-Δ12,14-prostaglandin J2 Induces Epithelial-to-mesenchymal Transition in Human Breast Cancer Cells and Promotes Fibroblast Activation

In inflammation-associated carcinogenesis, COX-2 is markedly overexpressed, resulting in accumulation of various prostaglandins. 15-deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is one of the terminal products of COX-2-catalyzed arachidonic acid catabolism with oncogenic potential. Epithelial-to-mesenchymal transition (EMT) is a process by which epithelial cells lose their polarity and adhesiveness, and thereby gain migratory and invasive properties. Treatment of human breast cancer MCF-7 cells with 15d-PGJ₂ induced EMT as evidenced by increased expression of Snail and ZEB1, with concurrent down-regulation of E-cadherin. Nuclear extract from 15d-PGJ₂-treated MCF-7 cells showed the binding of Snail and ZEB1 to E-box sequences present in the E-cadherin promoter, which accounts for repression of E-catherin expression. Unlike 15d-PGJ₂, its non-electrophilic analogue 9,10-dihydro-15d-PGJ₂ failed to induce EMT, suggesting that the α,β-unsaturated carbonyl group located in the cyclopentenone ring of 15d-PGJ₂ is essential for its oncogenic function. Notably, the mRNA level of interleukin-8 (IL-8)/CXCL8 was highly elevated in 15d-PGJ₂-stimulated MCF-7 cells. 15d-PGJ₂-induced up-regulation of IL-8/CXCL8 expression was abrogated by silencing of Snail short interfering RNA. Treatment of normal fibroblast with conditioned medium obtained from cultures of MCF-7 cells undergoing EMT induced the expression of activated fibroblast marker proteins, α-smooth muscle actin and fibroblasts activation protein-α. Co-culture of normal fibroblasts with 15d-PGJ₂-stimulated MCF-7 cells also activated normal fibroblast cells to cancer associated fibroblasts. Taken together, above findings suggest that 15d-PGJ₂ induces EMT through up-regulation of Snail expression and subsequent production of CXCL8 as a putative activator of fibroblasts, which may contribute to tumor-stroma interaction in inflammatory breast cancer microenvironment.

The chemistry, biology and pharmacology of the cyclopentenone prostaglandins

The cyclopentenone prostaglandins (CyPGs) are a small group compounds that are a subset of the eicosanoid superfamily, which are metabolites of arachidonic acid as well as other polyunsaturated fatty acids. The CyPGs are defined by a structural feature, namely, a five-membered carbocyclic ring containing an alfa-beta unsaturated keto group. The two most studied members are PGA₂ and 15d-PGJ₂ (15-deoxy-Δ12,14-prostaglandin J₂); other less studied members are PGA₁, Δ¹²-PGJ₂, and PGJ₂. They are involved in a number of biological activities including the ability to resolve chronic inflammation and the growth and survival of cells, particularly those of cancerous or neurological origin. Also, they can activate the prostaglandin DP2 receptor as well as the ligand-dependent transcription factor PPAR-gamma. Their ability to promote the resolution of chronic inflammation makes it of particular interest to have a good understanding of their actions. Since their discovery, the literature on the CyPGs has greatly expanded both in size and in scope; these reports are covered in the current review.

Synopsis

Akute entzündliche Reaktionen bzw. der akute Infekt mit Restitutio ad integrum laufen in einer perfekt modulierten Kaskade ab, bei dem eine akute inflammatorische Einleitungsphase von einer antiinflammatorischen Phase und einer Entzündungsauflösungsphase abgelöst werden.

15-Deoxy-Δ12,14-prostaglandin J2 Upregulates the Expression of 15-Hydroxyprostaglandin Dehydrogenase by Inducing AP-1 Activation and Heme Oxygenase-1 Expression in Human Colon Cancer Cells

Background

Abnormal upregulation of prostaglandin E₂ (PGE₂) is considered to be a key oncogenic event in the development and progression of inflammation-associated human colon cancer. It has been reported that 15-hydroxyprostaglandin dehydrogenase (15-PGDH), an enzyme catabolizing PGE₂, is ubiquitously downregulated in human colon cancer. 15-Deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂), a peroxisome proliferator-activated receptor γ ligand, has been shown to have anticarcinogenic activities. In this study, we investigate the effect of 15d-PGJ₂ on expression of 15-PGDH in human colon cancer HCT116 cells.

Methods

HCT116 cells were treated with 15d-PGJ₂ analysis. The expression of 15-PGDH in the treated cells was measured by Western blot analysis and RT-PCR. In addition, the cells were subjected to a 15-PGDH activity assay. To determine which transcription factor(s) and signaling pathway(s) are involved in 15d-PGJ₂-induced 15-PGDH expression, we performed a cDNA microarray analysis of 15d-PGJ₂-treated cells. The DNA binding activity of AP-1 was measured by an electrophoretic mobility shift assay. To determine whether the AP-1 plays an important role in the 15d-PGJ₂-induced 15-PGDH expression, the cells were transfected with siRNA of c-Jun, a major subunit of AP-1. To elucidate the upstream signaling pathways involved in AP-1 activation by 15d-PGJ₂, we examined its effect on phosphorylation of Akt by Western blot analysis in the presence or absence of kinase inhibitor.

Results

15d-PGJ₂ (10 μM) significantly upregulated 15-PGDH expression at the mRNA and protein levels in HCT-116 cells. 15-PGDH activity was also elevated by 15d-PGJ₂. We observed that genes encoding C/EBP delta, FOS-like antigen 1, c-Jun, and heme oxygenase-1 (HO-1) were most highly induced in the HCT116 cells following 15d-PGJ₂ treatment. 15d-PGJ₂ increased the DNA binding activity of AP-1. Moreover, transfection with specific siRNA against c-Jun significantly reduced 15-PGDH expression induced by 15d-PGJ₂. 15d-PGJ₂ activates Akt and a pharmacological inhibitor of Akt, LY294002, abrogated 15d-PGJ₂-induced 15-PGDH expression. We also observed that an inhibitor of HO-1, zinc protoporphyrin IX, also abrogated upregulation of 15-PGDH and down-regulation of cyclooxygenase-2 expression induced by 15d-PGJ₂.

Conclusions

These finding suggest that 15d-PGJ₂ upregulates the expression of 15-PGDH through AP-1 activation in colon cancer HCT116 cells.

15-Deoxy-Δ12,14-Prostaglandin J 2 Reinforces the Anti-Inflammatory Capacity of Endothelial Cells With a Genetically Determined NO Deficit

Rationale:

Fluid shear stress (FSS) maintains NOS-3 (endothelial NO synthase) expression. Homozygosity for the C variant of the T-786C single-nucleotide polymorphism of the NOS3 gene, which solely exists in humans, renders the gene less sensitive to FSS, resulting in a reduced endothelial cell (EC) capacity to generate NO. Decreased bioavailability of NO in the arterial vessel wall facilitates atherosclerosis. Consequently, individuals homozygous for the C variant have an increased risk for coronary heart disease (CHD).

Objective:

At least 2 compensatory mechanisms seem to minimize the deleterious effects of this single-nucleotide polymorphism in affected individuals, one of which is characterized herein.

Methods and Results:

Human genotyped umbilical vein ECs and THP-1 monocytes were used to investigate the role of 15-deoxy-Δ12,14-prostaglandin J 2 (15d-PGJ 2 ) in vitro. Its concentration in plasma samples from genotyped patients with CHD and age-matched CHD-free controls was determined using quantitative ultraperformance LC-MS/MS. Exposure of human ECs to FSS effectively reduced monocyte transmigration particularly through monolayers of CC-genotype ECs. Primarily in CC-genotype ECs, FSS elicited a marked rise in COX (cyclooxygenase)-2 and L-PGDS (lipocalin-type prostaglandin D synthase) expression, which appeared to be NO sensitive, and provoked a significant release of 15d-PGJ 2 over baseline. Exogenous 15d-PGJ 2 significantly reduced monocyte transmigration and exerted a pronounced anti-inflammatory effect on the transmigrated monocytes by downregulating, for example, transcription of the IL (interleukin)-1β gene ( IL1B ). Reporter gene analyses verified that this effect is due to binding of Nrf2 (nuclear factor [erythroid-derived 2]–like 2) to 2 AREs (antioxidant response elements) in the proximal IL1B promoter. In patients with CHD, 15d-PGJ 2 plasma levels were significantly upregulated compared with age-matched CHD-free controls, suggesting that this powerful anti-inflammatory prostanoid is part of an endogenous defence mechanism to counteract CHD.

Conclusions:

Despite a reduced capacity to form NO, CC-genotype ECs maintain a robust anti-inflammatory phenotype through an enhanced FSS-dependent release of 15d-PGJ 2 .

Regulation of Proteasome Activity by (Post-)transcriptional Mechanisms

Intracellular protein synthesis, folding, and degradation are tightly controlled processes to ensure proper protein homeostasis. The proteasome is responsible for the degradation of the majority of intracellular proteins, which are often targeted for degradation via polyubiquitination. However, the degradation rate of proteins is also affected by the capacity of proteasomes to recognize and degrade these substrate proteins. This capacity is regulated by a variety of proteasome modulations including (1) changes in complex composition, (2) post-translational modifications, and (3) altered transcription of proteasomal subunits and activators. Various diseases are linked to proteasome modulation and altered proteasome function. A better understanding of these modulations may offer new perspectives for therapeutic intervention. Here we present an overview of these three proteasome modulating mechanisms to give better insight into the diversity of proteasomes.

The 15d‑PGJ2 hydrogel ameliorates atopic dermatitis through suppression of the immune response

The present study examined the efficacy of the topical 15d-PGJ₂-poloxamer 407 hydrogel in an atopic dermatitis (AD) animal model. The 15d-PGJ₂ hydrogel was prepared and characterized. The examined rats possessed AD-Like cutaneous lesions, which were induced using 2,4-dinitrochlorobenzene, the rats were then treated with a hydrogel vehicle, 15d-PGJ₂ hydrogel or tacrolimus for 14 days. The rats were sacrificed and blood samples were collected to quantify the IgE levels. Subsequently, skin biopsies were stained with toluidine blue to identify mast cells and immunohistochemistry was performed for ROR-γt and TNF-α. Histological analyses demonstrated that 15d-PGJ₂ hydrogel significantly decreased mast cell infiltration (P<0.05) when compared with the AD-group. Tacrolimus at 0.1% exhibited decreased mast cell infiltration; however, this difference was not statistically significant from the AD-group. Topical 15d-PGJ₂ hydrogel and Tacrolimus 0.1% significantly reduced the serum levels of IgE (P<0.05) compared with the AD-group. Immunohistochemistry revealed a significant decrease in ROR-γt and TNF-α positive cell expression (P<0.05) in the 15d-PGJ₂ hydrogel group compared with the AD-group. In summary, topical administration of 15d-PGJ₂ hydrogel had a beneficial effect on AD symptoms, suggesting that this formulation may be a useful strategy for the treatment of AD.

Lipid metabolism in inflammation-related diseases

There are thousands of lipid species existing in cells, which belong to eight different categories. Lipids are the essential building blocks of cells. Recent studies have started to unveil the important functions of lipids in regulating cell metabolism. However, we are still at a very early stage in fully understanding the physiological and pathological functions of lipids. The application of lipidomics for studying lipid metabolism can provide a direct readout of the cellular status and broadens our understanding of the mechanisms that underpin metabolic disease states. This review provides an introduction to lipid metabolism and its role in modulating homeostasis and immunity. We also describe representative applications of lipidomics for studying lipid metabolism in inflammation-related diseases.

Biotinylation enhances the anticancer effects of 15d‑PGJ2 against breast cancer cells

15-Deoxy-∆12,14-prostaglandin J2 (15d‑PGJ2) is a natural agonist of peroxisome proliferator-activated receptor γ (PPARγ) that displays anticancer activity. Various studies have indicated that the effects of 15d‑PGJ2 are due to both PPARγ-dependent and -independent mechanisms. In the present study, we examined the effects of a biotinylated form of 15d‑PGJ2 (b‑15d‑PGJ2) on hormone-dependent MCF‑7 and triple‑negative MDA‑MB‑231 breast cancer cell lines. b‑15d‑PGJ2 inhibited cell proliferation more efficiently than 15d‑PGJ2 or the synthetic PPARγ agonist, efatutazone. b‑15d‑PGJ2 was also more potent than its non-biotinylated counterpart in inducing apoptosis. We then analyzed the mechanisms underlying this improved efficiency. It was found not to be the result of biotin receptor-mediated increased incorporation, since free biotin in the culture medium did not decrease the anti-proliferative activity of b‑15d‑PGJ2 in competition assays. Of note, b‑15d‑PGJ2 displayed an improved PPARγ agonist activity, as measured by transactivation experiments. Molecular docking analyses revealed a similar insertion of b‑15d‑PGJ2 and 15d‑PGJ2 into the ligand binding domain of PPARγ via a covalent bond with Cys285. Finally, PPARγ silencing markedly decreased the cleavage of the apoptotic markers, poly(ADP-ribose) polymerase 1 (PARP‑1) and caspase‑7, that usually occurs following b‑15d‑PGJ2 treatment. Taken together, our data indicate that biotinylation enhances the anti-proliferative and pro-apoptotic activity of 15d‑PGJ2, and that this effect is partly mediated via a PPARγ-dependent pathway. These results may aid in the development of novel therapeutic strategies for breast cancer treatment.

Inflammatory signaling and metabolic regulation by nitro-fatty acids

The addition of nitrogen dioxide (NO2) to the double bond of unsaturated fatty acids yields an array of electrophilic nitro-fatty acids (NO2-FA) with unique biochemical and signaling properties. During the last decade, NO2-FA have been shown to exert a protective role in various inflammatory and metabolic disorders. NO2-FA exert their biological effects primarily by regulating two central physiological adaptive responses: the canonical inflammatory signaling and metabolic pathways. In this mini-review, we summarize current knowledge on the regulatory role of NO2-FA in the inflammatory and metabolic response via regulation of nuclear factor kappa B (NF-κB) and peroxisome proliferator-activated receptor γ (PPARγ), master regulators of inflammation and metabolism. Moreover, the engagement of novel signaling and metabolic pathways influenced by NO2-FA, beyond NF-κB and PPAR signaling, is discussed herein.

Sensitive mass spectrometric assay for determination of 15-deoxy-Δ12,14-prostaglandin J2 and its application in human plasma samples of patients with diabetes

The determination of individual prostaglandins (PG) in humans is mainly performed in urine samples. The quantification of PGs in human plasma could improve the understanding of particular PG species under various physiological and pathological conditions. 15-Deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is a dehydrated downstream product of PGD₂ and is of high interest due to its recently discovered anti-inflammatory effects. Increasing availability of highly sensitive mass spectrometry allows the quantification of low abundant biomarkers like 15d-PGJ₂ in human plasma samples. Herein, a sensitive LC-MS/MS method for the determination of 15d-PGJ₂ was established. The method was validated according to the guidance of the American Food and Drug Administration and tested in plasma samples from patients with poorly controlled diabetes, considered to be a pro-inflammatory condition. Extraction of 15d-PGJ₂ was achieved with an easy-to-use liquid-liquid extraction by ethyl acetate following a methanol precipitation. The lower limit of quantification was 2.5 pg mL⁻¹ and linearity (R² = 0.998) was guaranteed between 2.5 and 500 pg mL⁻¹ for 15d-PGJ₂. Selectivity was assured by the use of two individual mass transitions (qualifier and quantifier). Precision and accuracy were validated in an inter- and intraday assay with a coefficient of variation below 11.8% (intraday) and 14.7% (interday). In diabetic patients with an HbA_1C > 9%, increased plasma concentrations of 15d-PGJ₂ compared to control plasma were measured. 15d-PGJ₂ correlated negatively with the inflammation marker C-reactive protein. The developed LC-MS/MS method represents a new possibility to quantify 15d-PGJ₂ with high specificity in human plasma samples. This may contribute to a better understanding of the potential anti-inflammatory effects of 15d-PGJ₂ in severe long-term pro-inflammatory disorders like diabetes, cancer, or cardiovascular disease.

15-Deoxy-Delta-12,14-Prostaglandin J2 Inhibits Lung Inflammation and Remodeling in Distinct Murine Models of Asthma

15-deoxy-Δ-12,14-prostaglandin J₂ (15d-PGJ₂) has been described as an anti-inflammatory lipid mediator in several in vitro and in vivo studies, but its effect on allergic pulmonary inflammation remains elusive. The aim of this study was to investigate the therapeutic potential of 15d-PGJ₂ based on distinct murine models of allergic asthma triggered by either ovalbumin (OVA) or house dust mite extract (HDM). Characteristics of lung inflammation, airway hyper-reactivity (AHR), mucus exacerbation, and lung remodeling in sensitized A/J mice treated or not with 15d-PGJ₂ were assessed. 15d-PGJ₂ treatments were carried out systemically or topically given via subcutaneous injection or intranasal instillation, respectively. Analyses were carried out 24 h after the last allergen provocation. Irrespective of the route of administration, 15d-PGJ₂ significantly inhibited the peribronchial accumulation of eosinophils and neutrophils, subepithelial fibrosis and also mucus exacerbation caused by either OVA or HDM challenge. The protective effect of 15d-PGJ₂ occurred in parallel with inhibition of allergen-induced AHR and lung tissue production of pro-inflammatory cytokines, such as interleukin (IL)-5, IL-13, IL-17, and TNF-α. Finally, 15d-PGJ₂ was found effective in inhibiting NF-κB phosphorylation upon HDM challenge as measured by Western blotting. In conclusion, our findings suggest that 15d-PGJ₂ can reduce crucial features of asthma, including AHR, lung inflammation, and remodeling in distinct murine models of the disease. These effects are associated with a decrease in lung tissue generation of pro-inflammatory cytokines by a mechanism related to downregulation of NF-κB phosphorylation.

Docosahexaenoic Acid Induces Expression of Heme Oxygenase-1 and NAD(P)H:quinone Oxidoreductase through Activation of Nrf2 in Human Mammary Epithelial Cells

Docosahexaenoic acid (DHA), an ω-3 fatty acid abundant in fish oils, has diverse health beneficial effects, such as anti-oxidative, anti-inflammatory, neuroprotective, and chemopreventive activities. In this study, we found that DHA induced expression of two representative antioxidant/cytoprotective enzymes, heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase (NQO1), in human mammary epithealial (MCF-10A) cells. DHA-induced upregulation of these enzymes was accompanied by enhanced translocation of the redox-sensitive transcription factor Nrf2 into the nucleus and its binding to antioxidant response element. Nrf2 gene silencing by siRNA abolished the DHA-induced expression of HO-1 and NQO1 proteins. When MCF-10A cells were transfected with mutant constructs in which the cysteine 151 or 288 residue of Keap1 was replaced by serine, DHA-induced expression of HO-1 and NQO1 was markedly reduced. Moreover, DHA activated protein kinase C (PKC)δ and induced Nrf2 phosphorylation. DHA-induced phosphorylation of Nrf2 was abrogated by the pharmacological PKCδ inhibitor rottlerin or siRNA knockdown of its gene expression. The antioxidants N-acetyl-l-cysteine and Trolox attenuated DHA-induced activation of PKCδ, phosphorylation of Nrf2, and and its target protein expression. In conclusion, DHA activates Nrf2, possibly through modification of critical Keap1 cysteine 288 residue and PKCδ-mediated phosphorylation of Nrf2, leading to upregulation of HO-1 and NQO1 expression.

15-Deoxy-Δ12,14-prostaglandin J2 alleviates hepatic ischemia-reperfusion injury in mice via inducing antioxidant response and inhibiting apoptosis and autophagy

Hepatic ischemia-reperfusion (I/R) injury is a common clinical impairment that occurs in many circumstances and leads to poor prognosis. Both apoptosis and autophagy have been shown to contribute to cell death in hepatic I/R injury. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) is one of the best-studied anti-inflammatory prostaglandins, which has been verified to exert anti-inflammatory and cell-protective functions in various types of cells and animal models. In this study we explored the effects of 15d-PGJ2 on both apoptosis and autophagy in mouse hepatic I/R injury and its possible mechanisms. A model of segmental (70%) hepatic warm ischemia was established in Balb/c mice, and the pathological changes in serum and liver tissues were detected at 6, 12, and 24 h post-surgery, while 15d-PGJ2 (2.5, 7.5, 15 μg, iv) was administered 30 min prior the surgery. Pretreatment with 15d-PGJ2 (7.5, 15 μg) significantly ameliorated I/R-induced hepatic injury evidenced by dose-dependent reduction of serum ALT and AST levels as well as alleviated tissue damages. 15d-PGJ2 pretreatment significantly decreased the serum TNF-α and IL-1β levels and the hepatic expression of F4/80, a major biomarker of macrophages. 15d-PGJ2 pretreatment upregulated the Bcl-2/Bax ratio, thus reducing the number of apoptotic cells in the livers. 15d-PGJ2 pretreatment considerably suppressed the expression of Beclin-1 and LC3, thus decreasing the number of autophagosomes in the livers. Furthermore, 15d-PGJ2 pretreatment activated Nrf2 and inhibited a ROS/HIF1α/BNIP3 pathway in the livers. Pretreatment with the PPARγ receptor blocker GW9662 (2 μg, ip) partly reversed the protective effects of 15d-PGJ2 on hepatic I/R injury. In conclusion, our results confirm the protective effect of 15d-PGJ2 on hepatic I/R injury, an effect that may rely on a reduction in the activation of Kupffer cells and on activation of the Nrf2 pathway, which lead to inhibition of ROS generation, apoptosis, and autophagy.

Effect of 15-Deoxy-Δ12,14-prostaglandin J2Nanocapsules on Inflammation and Bone Regeneration in a Rat Bone Defect Model

BACKGROUND

15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), one of the major metabolites from prostaglandin D2 in arachidonic acid metabolic pathway, has potential anti-inflammatory properties. The objective of this study was to explore the effects of 15d-PGJ2-loaded poly(D,L-lactide-co-glycolide) nanocapsules (15d-PGJ2-NC) on inflammatory responses and bone regeneration in local bone defect.

METHODS

The study was conducted on 96 Wistar rats from June 2014 to March 2016. Saline, unloaded nanoparticles, free 15d-PGJ2or 15d-PGJ2-NC, were delivered through a collagen vehicle inside surgically created transcortical defects in rat femurs. Interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and tumor necrosis factor-alpha (TNF-α) levels in the surrounding soft tissue were analyzed by Western blot and in the defect by quantitative real-time polymerase chain reaction over 14 days. Simultaneously, bone morphogenetic protein-6 (BMP-6) and platelet-derived growth factor-B (PDGF-B) messenger RNA (mRNA) in the defect were examined. New bone formation and EphrinB2 and osteoprotegerin (OPG) protein expression in the cortical defect were observed by Masson's Trichrome staining and immunohistochemistry over 28 days. Data were analyzed by one-way analysis of variance. Least-significant difference and Dunnett's T3 methods were used with a bilateral P< 0.05.

RESULTS

Application of l5d-PGJ2-NC (100 μg/ml) in the local bone defect significantly decreased IL-6, IL-1β, and TNF-α mRNA and protein, compared with saline-treated controls (P < 0.05). l5d-PGJ2-NC upregulated BMP-6 and PDGF-B mRNA (P < 0.05). New bone formation was observed in the cortical defect in l5d-PGJ2-NC-treated animals from 7th day onward (P < 0.001). Expression of EphrinB2 and OPG presented early on day 3 and persisted through day 28 in 15d-PGJ2-NC group (P < 0.05).

CONCLUSION

Stable l5d-PGJ2-NC complexes were prepared that could attenuate IL-6, IL-1β, and TNF-α expression, while increasing new bone formation and growth factors related to bone regeneration.

Synthesis and Evaluation of the Novel Prostamide, 15-Deoxy, Δ12,14-Prostamide J2, as a Selective Antitumor Therapeutic

15-deoxy, Δ^12,14-prostaglandin J₂-ethanolamide, also known as 15-deoxy, Δ^12,14-prostamide J₂ (15d-PMJ₂) is a novel product of the metabolism of arachidonoyl ethanolamide (AEA) by COX-2. 15d-PMJ₂ preferentially induced cell death and apoptosis in tumorigenic A431 keratinocytes and B16F10 melanoma cells compared with nontumorigenic HaCaT keratinocytes and Melan-A melanocytes. Activation of the ER stress execution proteins, PERK and CHOP10, was evaluated to determine whether this process was involved in 15d-PMJ₂ cell death. 15d-PMJ₂ increased the phosphorylation of PERK and expression of CHOP10 in tumorigenic but not nontumorigenic cells. The known ER stress inhibitors, salubrinal and 4-phenylbutaric acid, significantly inhibited 15d-PMJ₂-mediated apoptosis, suggesting ER stress as a primary apoptotic mediator. Furthermore, the reactive double bond present within the cyclopentenone structure of 15d-PMJ₂ was identified as a required moiety for the induction of ER stress apoptosis. The effect of 15d-PMJ₂ on B16F10 melanoma growth was also evaluated by dosing C57BL/6 mice with 0.5 mg/kg 15d-PMJ₂ Tumors of animals treated with 15d-PMJ₂ exhibited significantly reduced growth and mean weights compared with vehicle and untreated animals. TUNEL and IHC analysis of tumor tissues showed significant cell death and ER stress in tumors of 15d-PMJ₂-treated compared with control group animals. Taken together, these findings suggest that the novel prostamide, 15d-PMJ₂, possesses potent antitumor activity in vitro and in vivoMol Cancer Ther; 16(5); 838-49. ©2017 AACR.

15-Deoxy-Δ12,14-Prostaglandin J2 Modifies Components of the Proteasome and Inhibits Inflammatory Responses in Human Endothelial Cells

15-Deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is an electrophilic lipid mediator derived from PGD₂ with potent anti-inflammatory effects. These are likely to be due to the covalent modification of cellular proteins, via a reactive α,β-unsaturated carbonyl group in its cyclopentenone ring. This study was carried out to identify novel cellular target(s) for covalent modification by 15d-PGJ₂ and to investigate the anti-inflammatory effects of the prostaglandin on endothelial cells (EC). The data presented here show that 15d-PGJ₂ modifies and inhibits components of the proteasome and consequently inhibits the activation of the NF-κB pathway in response to TNF-α. This, in turn, inhibits the adhesion and migration of monocytes toward activated EC, by reducing the expression of adhesion molecules and chemokines in the EC. The effects are consistent with the covalent modification of 13 proteins in the 19S particle of the proteasome identified by mass spectrometry and the suppression of proteasome function, and were similar to the effects seen with a known proteasome inhibitor (MG132). The ubiquitin-proteasome system has been implicated in the regulation of several inflammatory processes and the observation that 15d-PGJ₂ profoundly affects the proteasome functions in human EC suggests that 15d-PGJ₂ may regulate the progression of inflammatory disorders such as atherosclerosis.

Human tolerogenic dendritic cells generated with protein kinase C inhibitor are optimal for functional regulatory T cell induction - A comparative study

Tolerogenic dendritic cells (tDCs) are a promising therapeutic tool for specific induction of immunological tolerance. Human tDCs can be generated ex vivo using various compounds. However, the compound(s) most suitable for clinical application remain undefined. We compared the tolerogenic properties of tDCs treated with protein kinase C inhibitor (PKCI), dexamethasone, vitamin D3 (Vit D3), rapamycin (Rapa), interleukin (IL)-10, transforming growth factor (TGF)-β, and a combination of peroxisome proliferator-activated receptor γ agonist and retinoic acid. All tDCs had a semi-mature DC phenotype. PKCI-, TGF-β-, and Rapa-tDCs showed CCR7 expression and migration to CCL19, but other tDCs showed little or none. PKCI- and IL-10-tDCs induced functional regulatory T cells more strongly than other tDCs. The tolerogenic properties of all tDCs were stable against proinflammatory stimuli. Furthermore, PKCI-tDCs were generated from patients with rheumatoid arthritis and primary Sjögren's syndrome. Therefore, PKCI-tDCs showed the characteristics best suited for tolerance-inducing therapy.

Targeting arachidonic acid pathway to prevent programmed hypertension in maternal fructose-fed male adult rat offspring

Hypertension can be programmed in response to nutritional insults in early life. Maternal high-fructose (HF) intake induced programmed hypertension in adult male offspring, which is associated with renal programming and arachidonic acid metabolism pathway. We examined whether early treatment with a soluble epoxide hydrolase (SEH) inhibitor, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) or 15-Deoxy-Δ^12,14-prostagandin J₂ (15dPGJ₂) can prevent HF-induced programmed hypertension. Pregnant Sprague Dawley rats received regular chow or chow supplemented with fructose (60% diet by weight) during the whole period of pregnancy and lactation. Four groups of male offspring were studied: control, HF, HF+AUDA and HF+15dPGJ_2. In HF+AUDA group, mother rats received AUDA 25 mg/L in drinking water during lactation. In the HF+15dPGJ₂ group, male offspring received 15dPGJ₂ 1.5 mg/kg body weight by subcutaneous injection once daily for 1 week after birth. Rats were sacrificed at 12 weeks of age. Maternal HF-induced programmed hypertension is associated with increased renal protein level of SEH and oxidative stress, which early AUDA therapy prevents. Comparison of AUDA and 15dPGJ₂ treatments demonstrated that AUDA was more effective in preventing HF-induced programmed hypertension. AUDA therapy increases angiotensin converting enzyme-2 (ACE2) protein levels and PGE₂ levels in adult offspring kidney exposed to maternal HF. 15dPGJ₂ therapy increases plasma asymmetric dimethylarginine (ADMA) levels and decreases L-arginine-to-ADMA ratio. Better understanding of the impact of arachidonic acid pathway, especially inhibition of SEH, on renal programming may aid in developing reprogramming strategy to prevent programmed hypertension in children exposed to antenatal HF intake.

Cyclopentenone-containing oxidized phospholipids and their isoprostanes as pro-resolving mediators of inflammation

Inflammation represents a powerful innate immune response that defends tissue homeostasis. However, the appropriate termination of inflammatory processes is essential to prevent the development of chronic inflammatory disorders. The resolution of inflammation is actively induced by specialized pro-resolving lipid mediators, which include eicosanoids, resolvins, protectins and maresins. The responsible pro-resolution pathways have emerged as promising targets for anti-inflammatory therapies since they mitigate excessive inflammation without compromising the anti-microbial defenses of the host. We have recently shown that the lipid peroxidation of membrane phospholipids, which is associated with inflammatory conditions, generates oxidized phospholipid (OxPL) species with potent pro-resolving activities. These pro-resolving OxPLs contain a cyclopentenone as their common determinant, and are structurally and functionally related to endogenous pro-resolving prostaglandins. Here, we review the regulation of inflammatory responses by OxPLs with particular focus on the bioactivities and structural characteristics of cyclopentenone-OxPLs, and discuss the impact of the responsible signaling pathways on inflammatory diseases. This article is part of a Special Issue entitled: Lipid modification and lipid peroxidation products in innate immunity and inflammation edited by Christoph J. Binder.

The role of endogenous opioid peptides in the antinociceptive effect of 15-deoxy(Δ12,14)-prostaglandin J2 in the temporomandibular joint

We have previously demonstrated that peripheral administration of 15d-PGJ2 in the Temporomandibular joint (TMJ) of rats can prevent nociceptor sensitization, mediated by peroxisome proliferator activated receptor-γ (PPAR-γ), and κ- and δ- opioid receptors. However, the mechanism that underlies the signaling of PPAR-γ (upon activation by 15d-PGJ2) to induce antinociception, and how the opioid receptors are activated via 15d-PGJ2 are not fully understood. This study demonstrates that peripheral antinociceptive effect of 15d-PGJ2 is mediated by PPAR-γ expressed in the inflammatory cells of TMJ tissues. Once activated by 15d-PGJ2, PPAR-γ induces the release of β-endorphin and dynorphin, which activates κ- and δ-opioid receptors in primary sensory neurons to induce the antinociceptive effect.

A nonsense mutation of Stim1 identified in stroke-prone spontaneously hypertensive rats decreased the store-operated calcium entry in astrocytes

We previously identified a nonsense mutation in the stromal interaction molecule-1 (Stim1) resulting in expression of a truncated STIM1 in the stroke-prone spontaneously hypertensive rat (SHRSP). In this study, we evaluated activity of the store-operated Ca(2+)-entry (SOCE) regulated by STIM1 to clarify putative functional abnormalities of the truncated STIM1. As a result, reduced SOCE activity resulting in suppression of cyclooxygenase-2 expression induced by SOCE was found in cultured astrocytes with the truncated STIM1 when compared with those with the wild-type. Our results indicated that the truncated STIM1 impaired Ca(2+) signaling regulated by SOCE and that the impaired SOCE activity might be responsible for pathological phenotypes in SHRSP.

Resolution of Inflammation: What Controls Its Onset?

An effective resolution program may be able to prevent the progression from non-resolving acute inflammation to persistent chronic inflammation. It has now become evident that coordinated resolution programs initiate shortly after inflammatory responses begin. In this context, several mechanisms provide the fine-tuning of inflammation and create a favorable environment for the resolution phase to take place and for homeostasis to return. In this review, we focus on the events required for an effective transition from the proinflammatory phase to the onset and establishment of resolution. We suggest that several mediators that promote the inflammatory phase of inflammation can simultaneously initiate a program for active resolution. Indeed, several events enact a decrease in the local chemokine concentration, a reduction which is essential to inhibit further infiltration of neutrophils into the tissue. Interestingly, although neutrophils are cells that characteristically participate in the active phase of inflammation, they also contribute to the onset of resolution. Further understanding of the molecular mechanisms that initiate resolution may be instrumental to develop pro-resolution strategies to treat complex chronic inflammatory diseases, in humans. The efforts to develop strategies based on resolution of inflammation have shaped a new area of pharmacology referred to as "resolution pharmacology."

Early postnatal treatment with soluble epoxide hydrolase inhibitor or 15-deoxy-Δ(12,14)-prostagandin J2 prevents prenatal dexamethasone and postnatal high saturated fat diet induced programmed hypertension in adult rat offspring

Prenatal dexamethasone (DEX) exposure, postnatal high-fat (HF) intake, and arachidonic acid pathway are closely related to hypertension. We tested whether a soluble epoxide hydrolase (SEH) inhibitor, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) or 15-deoxy-Δ(12,14)-prostagandin J2 (15dPGJ2) therapy can rescue programmed hypertension in the DEX+HF two-hit model. Four groups of Sprague Dawley rats were studied: control, DEX+HF, AUDA, and 15dPGJ2. Dexamethasone (0.1mg/kg body weight) was intraperitoneally administered to pregnant rats from gestational day 16-22. Male offspring received high-fat diet (D12331, Research Diets) from weaning to 4 months of age. In AUDA group, mother rats received 25mg/L in drinking water during lactation. In the 15dPGJ2 group, male offspring received 15dPGJ2 1.5mg/kg BW by subcutaneous injection once daily for 1 week after birth. We found postnatal HF diet aggravated prenatal DEX-induced programmed hypertension, which was similarly prevented by early treatment with AUDA or 15dPGJ2. The beneficial effects of AUDA and 15d-PGJ2 therapy include inhibition of SEH, increases of renal angiotensin converting enzyme-2 (ACE2) and angiotensin II type 2 receptor (AT2R) protein levels, and restoration of nitric oxide bioavailability. Better understanding of the impact of arachidonic acid pathway in the two-hit model will help prevent programmed hypertension in children exposed to corticosteroids and postnatal HF intake.