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Aberrant type 2 inflammatory responses are the underlying cause of the pathophysiology of allergic asthma, allergic rhinitis, and other atopic diseases, with an alarming prevalence in relevant parts of the Western world. A bulk of evidence points out the important role of the DP2 receptor in these inflammation processes. A screening of different polyunsaturated fatty acids at a fluorescence resonance energy transfer-based DP2 receptor conformation sensor expressed in human embryonic kidney (HEK) cells revealed an agonistic effect of the prostaglandin (PG)-D 2 precursor arachidonic acid on DP2 receptor activity of about 80% of the effect induced by PGD 2 In a combination of experiments at the conformation sensor and using a bioluminescence resonance energy transfer-based G protein activation sensor expressed together with DP2 receptor wild type in HEK cells, we found that arachidonic acid acts as a direct activator of the DP2 receptor, but not the DP1 receptor, in a concentration range considered physiologically relevant. Pharmacological inhibition of cyclooxygenases and lipoxygenases as well as cytochrome P450 did not lead to a diminished arachidonic acid response on the DP2 receptor, confirming a direct action of arachidonic acid on the receptor. SIGNIFICANCE STATEMENT: This study identified the prostaglandin precursor arachidonic acid to directly activate the DP2 receptor, a G protein-coupled receptor that is known to play an important role in type 2 inflammation., (Copyright © 2024 by The American Society for Pharmacology and Experimental Therapeutics.)

Senescent cells are characterized by multiple features such as increased expression of senescence-associated β-galactosidase activity (SA β-gal) and cell cycle inhibitors such as p21 or p16. They accumulate with tissue damage and dysregulate tissue homeostasis. In the context of skeletal muscle, it is known that agents used for chemotherapy such as Doxorubicin (Doxo) cause buildup of senescent cells, leading to the inhibition of tissue regeneration. Senescent cells influence the neighboring cells via numerous secreted factors which form the senescence-associated secreted phenotype (SASP). Lipids are emerging as a key component of SASP that can control tissue homeostasis. Arachidonic acid-derived lipids have been shown to accumulate within senescent cells, specifically 15d-PGJ 2 , which is an electrophilic lipid produced by the non-enzymatic dehydration of the prostaglandin PGD 2 . This study shows that 15d-PGJ 2 is also released by Doxo-induced senescent cells as an SASP factor. Treatment of skeletal muscle myoblasts with the conditioned medium from these senescent cells inhibits myoblast fusion during differentiation. Inhibition of L-PTGDS, the enzyme that synthesizes PGD 2 , diminishes the release of 15d-PGJ 2 by senescent cells and restores muscle differentiation. We further show that this lipid post-translationally modifies Cys184 of HRas in C2C12 mouse skeletal myoblasts, causing a reduction in the localization of HRas to the Golgi, increased HRas binding to Ras Binding Domain (RBD) of RAF Kinase (RAF-RBD), and activation of cellular Mitogen Activated Protein (MAP) kinase-Extracellular Signal Regulated Kinase (Erk) signaling (but not the Akt signaling). Mutating C184 of HRas prevents the ability of 15d-PGJ 2 to inhibit the differentiation of muscle cells and control the activity of HRas. This work shows that 15d-PGJ 2 released from senescent cells could be targeted to restore muscle homeostasis after chemotherapy., Competing Interests: SP, AB, AV, SS, MJ, RM, HL, MH, AR No competing interests declared, (© 2024, Pundlik et al.)

The DP2 receptor is a G-protein coupled receptor involved in allergic inflammation and is the target of recently developed antagonists already being tested in clinics. To get insights into DP2 receptor dynamics and to study its pharmacology on the level of the receptor, we constructed a fluorescence resonance energy transfer-based conformation sensor. The sensor reflects the selectivity profile of the DP2 receptor-wt and is suited for screening of agonists and antagonists due to its robust response. Furthermore, the sensor enables the direct measurement of DP2 receptor dynamics in real-time and revealed markedly distinct on- and off-rates of prostaglandin D 2 between DP2 and DP1 receptors, suggesting a different mechanism of ligand receptor interaction., (© 2024. The Author(s).)

Lung adenocarcinoma (LUADC) belongs to the most prevalent and lethal cancer types. As 15-deoxy-Δ12,14-prostaglandin J 2 (15d-PGJ 2 ) displays anti-oxidative, -inflammatory, and -cancer properties, we investigated whether this cyclopentenone PG, a stable degradation end-product of cyclooxygenase-generated PGD 2 , exerts beneficial effects in three LUADC cell lines (A549, H1299, H23). We here report that 15d-PGJ 2 had substantial cytotoxic effects in all three LUADC cell lines by promoting early apoptosis and inhibiting the cell cycle, proliferation, and migration. As indicators of cell malignancy, scratch closure and colony formation were significantly inhibited by 15d-PGJ 2 . 15d-PGJ 2 induced generation of ROS and subsequent activation of MAPKs. Expression of Nrf-2, a well-known tumor driver, was markedly diminished by 15d-PGJ 2 treatment. Although PPARγ, DP1, and DP2 are expressed in LUADC cells, blocking these receptors with specific inhibitors (SR16832 and BW245C) did not reverse 15d-PGJ 2 -mediated cytotoxicity, suggesting receptor-independent effects. 15d-PGJ 2 decreased SIRT1 expression in LUADC cells and the knockdown of SIRT1 diminished the cytotoxic effects of 15d-PGJ 2 . Importantly, 15d-PGJ 2 significantly reduced tumor growth using the chorioallantoic membrane (CAM) assay. The structural analog of 15d- PGJ 2 , 9,10-dihydro-15d-PGJ 2 (lacking the α,β-unsaturated ketone structural element), did not show any toxic effects in LUADC cells. Altogether, our findings suggest that 15d-PGJ 2 led to significantly reduced tumor growth and cell proliferation in three LUADC cell lines. The CAM assay results suggest that 15d-PGJ 2 is a suitable endogenous compound to interfere with LUADC tumor progression. We show that SIRT1 modulates the effects of 15d-PGJ 2 and may be used as a therapeutic target for LUADC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Prostaglandin D2 (PGD2) has been shown to restrict the occurrence and development of multiple cancers; nevertheless, its underlying molecular mechanism has not been fully elucidated. The present study investigated the effect of PGD2 on the biological function of the enriched gastric cancer stem cells (GCSCs), as well as its underlying molecular mechanism, to provide a theoretical basis and potential therapeutic drugs for gastric cancer (GC) treatment., Methods: The plasma PGD2 levels were detected by Enzyme-linked immunosorbent assay (ELISA). Silencing of lipocalin prostaglandin D synthetases (L-PTGDS) and prostaglandin D2 receptor 2 (PTGDR2) was carried out in GCSCs from SGC-7901 and HGC-27 cell lines. Cell Counting Kit-8, transwell, flow cytometry, and western blotting assays were used to determine cell viability, invasion, apoptosis, and stemness of GCSCs. In vivo xenograft models were used to assess tumor growth., Results: Clinically, it was found that the plasma PGD2 level decreased significantly in patients with GC. PGD2 suppressed viability, invasion, and stemness and increased the apoptosis of GCSCs. Downregulating L-PTGDS and PTGDR2 promoted viability, invasion, and stemness and reduced the apoptosis of GCSCs. Moreover, the inhibition of GCSCs induced by PGD2 was eliminated by downregulating the expression of PTGDR2. The results of in vivo experiments were consistent with those of in vitro experiments., Conclusion: Our data suggest that PGD2 may be an important marker and potential therapeutic target in the clinical management of GC. L-PTGDS/PTGDR2 may be one of the critical targets for GC therapy. The PGD2/PTGDR2 signal affects the viability, invasion, apoptosis, and stemness of GCSCs and prevents the progression of GC., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Prostaglandin (PG) D 2 , a commonly considered vasodilator through D prostanoid receptor-1 (DP1), might also evoke vasoconstriction via acting on the thromboxane (Tx)-prostanoid receptor (the original receptor of TxA 2 ; TP) and/or E prostanoid receptor-3 (one of the vasoconstrictor receptors of PGE 2 ; EP3). This study aimed to test the above hypothesis in the mouse renal vascular bed (main renal arteries and perfused kidneys) and/or mesenteric resistance arteries and determine how the vasoconstrictor mechanism influences the overall PGD 2 effect on systemic blood pressure under in vivo conditions. Experiments were performed on control wild-type (WT) mice and mice with deficiencies in TP (TP -/- ) and/or EP3 (EP3 -/- ). Here we show that PGD 2 indeed evoked vasoconstrictor responses in the above-mentioned tissues of WT mice, which were however not only reduced by TP -/- or EP3 -/- , but also reversed by TP -/- /EP3 -/- in some of the above tissues (mesenteric resistance arteries or perfused kidneys) to dilator reactions that were reduced by non-selective DP antagonism. A slight or mild pressor response was also observed with PGD 2 under in vivo conditions, and this was again reversed to a depressor response in TP -/- or TP -/- /EP3 -/- mice. Non-selective DP antagonism reduced the PGD 2 -evoked depressor response in TP -/- /EP3 -/- mice as well. These results thus demonstrate that like other PGs, PGD 2 activates TP and/or EP3 to evoke vasoconstrictor activities, which can outweigh its concurrent vasodepressor activity mediated mainly through DP1, and hence result in a pressor response, although the response might only be of a slight or mild extent., Competing Interests: Declaration of competing interest None., (Copyright © 2023 Elsevier B.V. All rights reserved.)

15-deoxy-Δ 12,14 -prostaglandin J 2 (15d-PGJ 2 ) exhibited potential to alleviate liver inflammation in chronic injury but was less studied in acute injury. Acute liver injury was associated with elevated macrophage migration inhibitory factor (MIF) levels in damaged hepatocytes. This study aimed to investigate the regulatory mechanism of hepatocyte-derived MIF by 15d-PGJ 2 and its subsequent impact on acute liver injury. In vivo, mouse models were established by carbon tetrachloride (CCl 4 ) intraperitoneal injection, with or without 15d-PGJ 2 administration. 15d-PGJ 2 treatment reduced the necrotic areas induced by CCl 4 . In the same mouse model constructed using enhanced green fluorescent protein (EGFP)-labeled bone marrow (BM) chimeric mice, 15d-PGJ 2 reduced CCl 4 induced BM-derived macrophage (BMM, EGFP + F4/80 + ) infiltration and inflammatory cytokine expression. Additionally, 15d-PGJ 2 down-regulated liver and serum MIF levels; liver MIF expression was positively correlated with BMM percentage and inflammatory cytokine expression. In vitro, 15d-PGJ 2 inhibited Mif expression in hepatocytes. In primary hepatocytes, reactive oxygen species inhibitor (NAC) showed no effect on MIF inhibition by 15d-PGJ 2 ; PPARγ inhibitor (GW9662) abolished 15d-PGJ 2 suppressed MIF expression and antagonists (troglitazone, ciglitazone) mimicked its function. In Pparg silenced AML12 cells, the suppression of MIF by 15d-PGJ 2 was weakened; 15d-PGJ 2 promoted PPARγ activation in AML 12 cells and primary hepatocytes. Furthermore, the conditioned medium of recombinant MIF- and lipopolysaccharide-treated AML12 respectively promoted BMM migration and inflammatory cytokine expression. Conditioned medium of 15d-PGJ 2 - or siMif-treated injured AML12 suppressed these effects. Collectively, 15d-PGJ 2 activated PPARγ to suppress MIF expression in injured hepatocytes, reducing BMM infiltration and pro-inflammatory activation, ultimately alleviating acute liver injury., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Purpose: The purpose of this study was to investigate the impact of prostaglandin D2 (PGD2) receptor 2 (DP2) on choroidal neovascularization (CNV) formation in mice., Methods: Using a laser-induced CNV model, the CNV size of wild-type (WT) mice treated with DP2 antagonist (CAY10471 or OC000459) was compared with that of untreated mice. Vascular endothelial growth factor (VEGF) and MCP-1 levels were also compared between the two groups. Similar experiments were performed comparing DP2 knockout (DP2KO) mice with WT mice (8 and 56 weeks old). The number of infiltrating macrophages to laser spots was also compared between the WT and DP2KO mice. We administered a DP2 antagonist to 15-methyl PGD2 (a DP2 agonist)-stimulated ARPE-19 cells and measured VEGF secretion by enzyme-linked immunosorbent assay. Tube formation assay was performed on human umbilical vein endothelial cells with or without a DP2 antagonist., Results: CNV sizes were significantly smaller in mice treated with CAY10471 or OC000459 than in those treated with vehicle. Similarly, the CNV size of DP2KO mice was significantly smaller than that of WT mice. The number of macrophages at laser spots in DP2KO mice was significantly lower than that in WT mice. The VEGF concentration of lasered DP2KO mice's eyes was significantly lower than that of lasered WT mice' eyes. DP2 antagonist treatment suppressed VEGF secretion in ARPE-19 cells under 15-methyl PGD2 stimulation. The tube formation assay suggested that lumen formation was inhibited by a DP2 antagonist., Conclusions: DP2 blockade attenuated choroidal neovascularization., Translational Relevance: Drugs targeting DP2 are potentially a novel treatment for age-related macular degeneration.

Prostaglandin D 2 (PGD 2 ) is one of the most potent endogenous sleep-promoting molecules. However, the cellular and molecular mechanisms of the PGD 2 -induced activation of sleep-promoting neurons in the ventrolateral preoptic nucleus (VLPO), the major nonrapid eye movement (NREM)-sleep center, still remains unclear. We here show that PGD 2 receptors (DP 1 ) are not only expressed in the leptomeninges but also in astrocytes from the VLPO. We further demonstrate, by performing real-time measurements of extracellular adenosine using purine enzymatic biosensors in the VLPO, that PGD 2 application causes a 40% increase in adenosine level, via an astroglial release. Measurements of vasodilatory responses and electrophysiological recordings finally reveal that, in response to PGD 2 application, adenosine release induces an A 2A R-mediated dilatation of blood vessels and activation of VLPO sleep-promoting neurons. Altogether, our results unravel the PGD 2 signaling pathway in the VLPO, controlling local blood flow and sleep-promoting neurons, via astrocyte-derived adenosine.

Background: Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-dependent nuclear receptor and highly expressed in human and rodent lungs. 15-Deoxy-delta- 12,14 -prostaglandin J2 (15d-PGJ2), known for cyclopentenone prostaglandin, is the endogenous ligand of PPARγ. However, the associations among PPARγ, 15d-PGJ2 and chronic obstructive pulmonary disease (COPD) were unclear., Methods: All 130 fasting blood samples and 40 lung specimens were obtained from COPD patients and control subjects. Serum 15d-PGJ2 was detected by ELISA. The expressions of oxidative stress indicators were measured using western blotting and PPARγ nuclei were evaluated with immunohistochemistry in lungs. The associations among serum 15d-PGJ2, pulmonary PPARγ and oxidative stress indicators, and COPD were estimated., Results: Serum 15d-PGJ2 was reduced in COPD patients compared with healthy volunteers. Linear and logistic regression analysis indicated that serum 15d-PGJ2 was positively associated with pulmonary function in COPD patients. In addition, PPARγ-positive nuclei were reduced and oxidative stress indicators, included HO-1 and NOX-4, were increased in lungs of COPD patients. Further correlative analysis suggested that pulmonary function parameters was positively correlated with serum 15d-PGJ2 and pulmonary PPARγ-positive nuclei, inversely related to oxidative stress indicators in lungs of COPD patients. Pretreatment with 15d-PGJ2 obviously attenuated TNFα-induced oxidative stress in BEAS-2B cells., Conclusions: Serum 15d-PGJ2 and pulmonary PPARγ are reduced, and oxidative stress is elevated in COPD patients. Serum 15d-PGJ2 is inversely associated with oxidative stress in COPD patients., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Melanoma is the deadliest form of skin cancer in the US. Although immunotherapeutic checkpoint inhibitors and small-molecule kinase inhibitors have dramatically increased the survival of patients with melanoma, new or optimized therapeutic approaches are still needed to improve outcomes. 15-deoxy-Δ 12,14 -prostamide J 2 (15d-PMJ 2 ) is an investigational small-molecule that induces ER stress-mediated apoptosis selectively in tumor cells. Additionally, 15d-PMJ2 reduces melanoma growth in vivo . To assess the chemotherapeutic potential of 15d-PMJ 2 , the current study sought to uncover molecular pathways by which 15d-PMJ 2 exerts its antitumor activity. B16F10 melanoma and JWF2 squamous cell carcinoma cell lines were cultured in the presence of pharmacological agents that prevent ER or oxidative stress as well as Ca 2+ channel blockers to identify mechanisms of 15d-PMJ 2 cell death. Our data demonstrated the ER stress protein, PERK, was required for 15d-PMJ 2 -induced death. PERK activation triggered the release of ER-resident Ca 2+ through an IP 3 R sensitive pathway. Increased calcium mobilization led to mitochondrial Ca 2+ overload followed by mitochondrial permeability transition pore (mPTP) opening and the deterioration of mitochondrial respiration. Finally, we show the electrophilic double bond located within the cyclopentenone ring of 15d-PMJ 2 was required for its activity. The present study identifies PERK/IP3R/mPTP signaling as a mechanism of 15d-PMJ 2 antitumor activity.

Inhibition of microsomal prostaglandin E synthase-1 (mPGES-1) results in decreased production of proinflammatory PGE 2 and can lead to shunting of PGH 2 into the prostaglandin D 2 (PGD 2 )/15-deoxy-Δ 12,14 -prostaglandin J 2 (15dPGJ 2 ) pathway. 15dPGJ 2 forms Michael adducts with thiol-containing biomolecules such as GSH or cysteine residues on target proteins and is thought to promote resolution of inflammation. We aimed to elucidate the biosynthesis and metabolism of 15dPGJ 2 via conjugation with GSH, to form 15dPGJ 2 -glutathione (15dPGJ 2 -GS) and 15dPGJ 2 -cysteine (15dPGJ 2 -Cys) conjugates and to characterize the effects of mPGES-1 inhibition on the PGD 2 /15dPGJ 2 pathway in mouse and human immune cells. Our results demonstrate the formation of PGD 2 , 15dPGJ 2 , 15dPGJ 2 -GS, and 15dPGJ 2 -Cys in RAW264.7 cells after lipopolysaccharide stimulation. Moreover, 15dPGJ 2 -Cys was found in lipopolysaccharide-activated primary murine macrophages as well as in human mast cells following stimulation of the IgE-receptor. Our results also suggest that the microsomal glutathione S-transferase 3 is essential for the formation of 15dPGJ 2 conjugates. In contrast to inhibition of cyclooxygenase, which leads to blockage of the PGD 2 /15dPGJ 2 pathway, we found that inhibition of mPGES-1 preserves PGD 2 and its metabolites. Collectively, this study highlights the formation of 15dPGJ 2 -GS and 15dPGJ 2 -Cys in mouse and human immune cells, the involvement of microsomal glutathione S-transferase 3 in their biosynthesis, and their unchanged formation following inhibition of mPGES-1. The results encourage further research on their roles as bioactive lipid mediators., Competing Interests: Conflict of Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. P.-J. J. is engaged in Gesynta Pharma AB, a company that develops mPGES-1 inhibitors., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Prostaglandins (PGs) are highly reactive small lipophilic molecules derived from polyunsaturated fatty acids of the cell membrane and play a key role in the resolution of inflammation processes. 15-deoxy-Δ 12,14 -PGJ 2 (15dPGJ 2 ) is a cyclopentenone PG (CyPG) of the J series with anti-inflammatory, anti-proliferative and pro-apoptotic effects. This CyPG can signal through: (i) the PGD 2 receptor (DP2) and peroxisome proliferator-activated receptor γ (PPARγ) or (ii) by covalent binding to protein nucleophiles, such as, thiols groups of cysteine, lysine or histidine via a Michael addition reaction, modifying its structure and function. In this work we show that acidophilic granulocytes (AGs) of gilthead seabream (Sparus aurata L.), the functional equivalent to mammalian neutrophils, constitutively expressed ppara, pparb and pparg genes, the latter showing the highest expression and up-regulation when stimulated by bacterial DNA. In addition, we tested the ability of 15dPGJ 2, and its biotinylated analog, as well as several PPARγ ligands, to modulate reactive oxygen species (ROS) and/or cytokines production during a Toll like receptor (TLR)-mediated granulocyte response. Thus, 15dPGJ 2 was able to significantly decrease bacterial DNA-induced ROS production and transcript levels of pparg, interleukin-1β (il1b) and prostaglandin-endoperoxide synthase 2 (ptgs2). In contrast, its biotinylated analog was less potent and a higher dose was required to elicit the same effects on ROS production and cytokine expression. In addition, different PPARγ agonists were able to mimic the effects of 15dPGJ 2 . Conversely, the PPARγ antagonist T007097 abolished the effect of 15dPGJ 2 on DNA bacterial-induced ROS production. Surprisingly, transactivation assays revealed that both 15dPGJ 2 and its biotinylated analog signaled via Pparα and Pparβ, but not by Pparγ. These results were further confirmed by HPLC/MS analysis, where Pparβ was identified as an interactor of biotin-15dPGJ 2 in naïve and DNA-stimulated leukocytes. Taken together, our data show that 15dPGJ 2 acts both through Ppar activation and covalent binding to proteins in fish granulocytes and identify for the first time in vertebrates a role for Pparα and Pparβ in the resolution of inflammation mediated by 15dPGJ 2 ., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Pulmonary arterial hypertension (PAH) is a progressive disease that significantly endangers human health, where metabolism may drive pathogenesis: a shift from mitochondrial oxidation to glycolysis occurs in diseased pulmonary vessels and the right ventricle. An increase in pulmonary vascular resistance in patients with heart failure with a preserved ejection fraction portends a poor prognosis. Luteolin exists in numerous foods and is marketed as a dietary supplement assisting in many disease treatments. However, little is known about the protective effect of luteolin on metabolism disorders in diseased pulmonary vessels. In this study, we found that luteolin apparently reversed the pulmonary vascular remodeling of PAH rats by inhibiting the abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs). Moreover, network pharmacology and metabolomics results revealed that the arachidonic acid pathway, amino acid pathway and TCA cycle were dysregulated in PAH. A total of 14 differential metabolites were significantly changed during the PAH, including DHA, PGE2, PGD2, LTB4, 12-HETE, 15-HETE, PGF2α, and 8-iso-PGF2α metabolites in the arachidonic acid pathway, and L-asparagine, oxaloacetate, N -acetyl-L-ornithine, butane diacid, ornithine, glutamic acid metabolites in amino acid and TCA pathways. However, treatment with luteolin recovered the LTB4, PGE2, PGD2, 12-HETE, 15-HETE, PGF2α and 8-iso-PGF2α levels close to normal. Meanwhile, we showed that luteolin also downregulated the gene and protein levels of COX 1, 5-LOX, 12-LOX, and 15-LOX in the arachidonic acid pathway. Collectively, this work highlighted the metabolic mechanism of luteolin-protected PAH and showed that luteolin would hold great potential in PAH prevention.

We investigated the relevance of the prostaglandin D2 pathway in Alzheimer's disease, because prostaglandin D2 is a major prostaglandin in the brain. Thus, its contribution to Alzheimer's disease merits attention, given the known impact of the prostaglandin E2 pathway in Alzheimer's disease. We used the TgF344-AD transgenic rat model because it exhibits age-dependent and progressive Alzheimer's disease pathology. Prostaglandin D2 levels in hippocampi of TgF344-AD and wild-type littermates were significantly higher than prostaglandin E2. Prostaglandin D2 signals through DP1 and DP2 receptors. Microglial DP1 receptors were more abundant and neuronal DP2 receptors were fewer in TgF344-AD than in wild-type rats. Expression of the major brain prostaglandin D2 synthase (lipocalin-type PGDS) was the highest among 33 genes involved in the prostaglandin D2 and prostaglandin E2 pathways. We treated a subset of rats (wild-type and TgF344-AD males) with timapiprant, a potent highly selective DP2 antagonist in development for allergic inflammation treatment. Timapiprant significantly mitigated Alzheimer's disease pathology and cognitive deficits in TgF344-AD males. Thus, selective DP2 antagonists have potential as therapeutics to treat Alzheimer's disease., (© 2022 Wallace et al.)

Background: In diabetes, delayed wound healing was considered as the result of excessive recruitment and retention of pro-inflammatory cells and factors. Hematopoietic prostaglandin D synthase (HPGDS) was identified from differently expressed genes of diabetic human foot skin. HPGDS is responsible for the production of prostaglandin D2 (PGD2), an inflammatory mediator. Therefore, we aim to explore whether HPGDS could be a therapeutic target in the diabetic wound (DW)., Method: In this study, we compared gene expression profilings of diabetic human foot skin and non-diabetic human foot skin from the Gene Expression Omnibus database. We detected the characteristics of immune components in diabetic mice wound and investigated the role and underlying mechanism of the differently expressed Hpgds for the diabetic wound healing. For in vivo studies, we engineered ADSC to overexpress Hpgds (ADSC Hpgds ) and evaluated its effects on diabetic wound healing using a full-thickness skin wound model. For in vitro studies, we evaluated the role of ADSC Hpgds conditioned medium and PGD2 on Lipopolysaccharide (LPS) induced macrophage., Results: Hpgds was significantly down-regulated in type 2 diabetic mice wound and its deficiency delayed normal wound healing. ADSC Hpgds accelerated DW healing by reducing neutrophil and CD8T cell recruitment, promoting M2 macrophage polarization and increasing the production of growth factors. ADSC Hpgds conditioned medium showed superior capability in promoting M2 macrophage transition than conditioned medium derived from ADSC alone., Conclusion: Our results demonstrated that Hpgds is required for wound healing, and ADSC Hpgds could accelerate DW healing by improving anti-inflammatory state and normalizing the proliferation phase of wound healing in mice. These findings provide a new insight in the therapeutic strategy of diabetic wound., (© 2022. The Author(s).)

T follicular helper (Tfh) cells are a subset of CD4+ T cells essential in immunity and have a role in helping B cells produce antibodies against pathogens. However, their role during cancer progression remains unknown. The mechanism of action of Tfh cells remains elusive because contradictory data have been reported on their protumor or antitumor responses in human and murine tumors. Like Tfh cells, Th2 cells are also involved in humoral immunity and are regularly associated with tumor progression and poor prognosis, mainly through their secretion of IL4. Here, we showed that Tfh cells expressed hematopoietic prostaglandin D2 (PGD2) synthase in a pSTAT1/pSTAT3-dependent manner. Tfh cells produced PGD2, which led to recruitment of Th2 cells via the PGD2 receptor chemoattractant receptor homologous molecule expressed on Th type 2 cells (CRTH2) and increased their effector functions. This cross-talk between Tfh and Th2 cells promoted IL4-dependent tumor growth. Correlation between Th2 cells, Tfh cells, and hematopoietic PGD2 synthase was observed in different human cancers and associated with outcome. This study provides evidence that Tfh/Th2 cross-talk through PGD2 limits the antitumor effects of Tfh cells and, therefore, could serve as a therapeutic target., (©2022 American Association for Cancer Research.)

Transcriptional factor EB (TFEB), a master regulator of autophagy and lysosomal biogenesis, is generally regarded as a pro-survival factor. Here, we identify that besides its effect on autophagy induction, TFEB exerts a pro-apoptotic effect in response to the cyclopentenone prostaglandin 15-deoxy-∆- 12,14 -prostaglandin J2 (15d-PGJ2). Specifically, 15d-PGJ2 promotes TFEB translocation from the cytoplasm into the nucleus to induce autophagy and lysosome biogenesis via reactive oxygen species (ROS) production rather than mTORC1 inactivation. Surprisingly, TFEB promotes rather than inhibits apoptosis in response to 15d-PGJ2. Mechanistically, ROS-mediated TFEB translocation into the nucleus transcriptionally upregulates the expression of ATF4, which is required for apoptosis elicited by 15d-PGJ2. Additionally, inhibition of TFEB activation by ROS scavenger N-acetyl cysteine or inhibition of protein synthesis by cycloheximide effectively compromises ATF4 upregulation and apoptosis in response to 15d-PGJ2. Collectively, these results indicate that ROS-induced TFEB activation exerts a novel role in promoting apoptosis besides its role in regulating autophagy in response to 15d-PGJ2. This work not only evidences how TFEB is activated by 15d-PGJ2, but also unveils a previously unexplored role of ROS-dependent activation of TFEB in modulating cell apoptosis in response to 15d-PGJ2., (© 2021. The Author(s), under exclusive licence to CPS and SIMM.)

We previously reported that prostaglandin (PG)D2 and its isosteric analog, 11-deoxy-11-methylene-PGD2 (11d-11m-PGD2), promote adipogenesis in 3T3-L1 cells during the maturation phase. Focusing on the differentiation phase, although both PGs inhibited adipogenesis, this effect was canceled out by PGI2 and PGJ2 derivatives. Thus, PGD2 and 11d-11m-PGD2 play different roles during the phases, but do not affect PGI2- and PGJ2-derivative-induced adipogenesis., (© The Author(s) 2022. Published by Oxford University Press on behalf of Japan Society for Bioscience, Biotechnology, and Agrochemistry.)

The pathogenesis of cerebral ischemia-reperfusion (I/R) injury is complex and does not exhibit an effective strategy. Maternal inflammation represents one of the most important factors involved in the etiology of brain injury in newborns. We aimed to investigate the effect of maternal inflammation on offspring susceptibility to cerebral I/R injury and the mechanisms by which it exerts its effects. Pregnant SD rats were intraperitoneally injected with LPS (300  μ g/kg/day) at gestational days 11, 14, and 18. Pups were subjected to MCAO/R on postnatal day 60. Primary neurons were obtained from postnatal day 0 SD rats and subjected to OGD/R. Neurological deficits, brain injury, neuronal viability, neuronal damage, and neuronal apoptosis were assessed. Oxidative stress and inflammation were evaluated, and the expression levels of COX-2/PGD2/DP pathway-related proteins and apoptotic proteins were detected. Maternal LPS exposure significantly increased the levels of oxidative stress and inflammation, significantly activated the COX-2/PGD2/DP 2 pathway, and increased proapoptotic protein expression. However, maternal LPS exposure significantly decreased the antiapoptotic protein expression, which subsequently increased neurological deficits and cerebral I/R injury in offspring rats. The corresponding results were observed in primary neurons. Moreover, these effects of maternal LPS exposure were reversed by a COX-2 inhibitor and DP 1 agonist but exacerbated by a DP 2 agonist. In conclusion, maternal inflammatory exposure may increase offspring susceptibility to cerebral I/R injury. Moreover, the underlying mechanism might be related to the activation of the COX-2/PGD2/DP 2 pathway. These findings provide a theoretical foundation for the development of therapeutic drugs for cerebral I/R injury., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2022 Yuke Li et al.)

Excessive production of reactive oxygen species (ROS) by NADPH oxidase (Nox) resulted in inflammation. The negative regulator of ROS (NRROS) dampens ROS generation during inflammatory responses. 15-Deoxy-∆12,14-prostaglandin J 2 (15d-PGJ 2 ) exhibits neuroprotective effects on central nervous system (CNS). However, whether 15d-PGJ 2 -induced NRROS expression was unknown in rat brain astrocytes (RBA-1). NRROS expression was determined by Western blot, RT/real-time PCR, and promoter activity assays. The signaling components were investigated using pharmacological inhibitors or specific siRNAs. The interaction between transcription factors and the NRROS promoter was investigated by chromatin immunoprecipitation assay. Upregulation of NRROS on the hydrogen peroxide (H 2 O 2 )-mediated ROS generation and interleukin 6 (IL-6) secretion was measured. 15d-PGJ 2 -induced NRROS expression was mediated through PI3K/Akt-dependent activation of Sp1 and FoxO1 and established the essential promoter regions. We demonstrated that 15d-PGJ 2 activated PI3K/Akt and following by cooperation between phosphorylated nuclear FoxO1 and Sp1 to initiate the NRROS transcription. In addition, Nrf2 played a key role in NRROS expression induced by 15d-PGJ 2 which was mediated through its phosphorylation. Finally, the NRROS stable clones attenuated the H 2 O 2 -induced ROS generation and expression of IL-6 through suppressing the Nox-2 activity. These results suggested that 15d-PGJ 2 -induced NRROS expression is mediated through a PI3K/Akt-dependent FoxO1 and Sp1 phosphorylation, and Nrf2 cascade, which suppresses ROS generation through attenuating the p47 phox phosphorylation and gp91 phox formation and IL-6 expression in RBA-1 cells. These results confirmed the mechanisms underlying 15d-PGJ 2 -induced NRROS expression which might be a potential strategy for prevention and management of brain inflammatory and neurodegenerative diseases., (© 2021. The Author(s).)

The current study was conducted with the aim to investigate effects of PPARγ ligands on synthesis of nuclear receptor κB (NF-κB) and selected cytokines (IL-1β, IFNγ, TNFα, IL-4, IL-10, LIF) in the pig myometrium on days 14-15 of the estrous cycle (late-luteal phase) and days 14-15 of the gestational period (beginning of embryonic implantation). The myometrial slices were incubated in vitro for 6 h in medium containing PPARγ ligands, agonists: 15d-prostaglandin J 2 or pioglitazone, and antagonist - T0070907. The mRNA transcript and protein abundances were evaluated in tissues and culture medium. During the estrous cycle, PPARγ ligands did not have an effect on the mRNA transcript abundance of the immune response mediators used for treatments. The IL-10 protein abundance in the tissue was less when there was inclusions of pioglitazone in the medium, while the treatment with T0070907 resulted in a larger abundance of NF-κB, IL-1β (in the tissue) and IL-4 (in tissue and culture media). During the gestational period, pioglitazone or PGJ 2 suppressed mRNA IFNγ and IL-10 transcript and protein abundances (in the tissue and culture media), whereas there was an enhanced NF-κB protein abundance (in the tissue). Treatment with T0070907 had diverse effects (e.g., for NFκB inhibited mRNA transcript abundance or enhanced protein abundance). The observed changes are related mainly in tissues from pregnant animals. Responses to PPARγ antagonist are indicative of the possible involvement of PPARγ-independent factors as well as ligand-independent activation of the receptor, ligand selectivity/functionality or tissue receptivity to the factors evaluated., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Osteosarcoma (OS) is the most common type of bone tumor, and has limited therapy options. 15-Deoxy-Δ 12,14 -prostaglandin J 2 (15d-PGJ 2 ) has striking anti-tumor effects in various tumors. Here, we investigated molecular mechanisms that mediate anti-tumor effects of 15d-PGJ 2 in different OS cell lines. Human U2-OS and Saos-2 cells were treated with 15d-PGJ 2 and cell survival was measured by MTT assay. Cell proliferation and motility were investigated by scratch assay, the tumorigenic capacity by colony forming assay. Intracellular ROS was estimated by H 2 DCFDA. Activation of MAPKs and cytoprotective proteins was detected by immunoblotting. Apoptosis was detected by immunoblotting and Annexin V/PI staining. The ex ovo CAM model was used to study growth capability of grafted 15d-PGJ 2 -treated OS cells, followed by immunohistochemistry with hematoxylin/eosin and Ki-67. 15d-PGJ 2 substantially decreased cell viability, colony formation and wound closure capability of OS cells. Non-malignant human osteoblast was less affected by 15d-PGJ 2 . 15d-PGJ 2 induced rapid intracellular ROS production and time-dependent activation of MAPKs (pERK1/2, pJNK and pp38). Tempol efficiently inhibited 15d-PGJ 2 -induced ERK1/2 activation, while N-acetylcystein and pyrrolidine dithiocarbamate were less effective. Early but weak activation of cytoprotective proteins was overrun by induction of apoptosis. A structural analogue, 9,10-dihydro-15d-PGJ 2 , did not show toxic effects in OS cells. In the CAM model, we grafted OS tumors with U2-OS, Saos-2 and MG-63 cells. 15d-PGJ 2 treatment resulted in significant growth inhibition, diminished tumor tissue density, and reduced tumor cell proliferation for all cell lines. Our in vitro and CAM data suggest 15d-PGJ 2 as a promising natural compound to interfere with OS tumor growth.

Background: Prostaglandin D 2 (PGD 2 ) signaling via prostaglandin D 2 receptor 2 (DP 2 ) contributes to atopic and non-atopic asthma. Inhibiting DP 2 has shown therapeutic benefit in certain subsets of asthma patients, improving eosinophilic airway inflammation. PGD 2 metabolites prolong the inflammatory response in asthmatic patients via DP 2 signaling. The role of PGD 2 metabolites on eosinophil and ILC2 activity is not fully understood., Methods: Eosinophils and ILC2s were isolated from peripheral blood of atopic asthmatic patients. Eosinophil shape change, ILC2 migration and IL-5/IL-13 cytokine secretion were measured after stimulation with seven PGD 2 metabolites in presence or absence of the selective DP 2 antagonist fevipiprant., Results: Selected metabolites induced eosinophil shape change with similar nanomolar potencies except for 9α,11β-PGF 2 . Maximal values in forward scatter of eosinophils were comparable between metabolites. ILC2s migrated dose-dependently in the presence of selected metabolites except for 9α,11β-PGF 2 with EC 50 values ranging from 17.4 to 91.7 nM. Compared to PGD 2 , the absolute cell migration was enhanced in the presence of Δ 12 -PGD 2 , 15-deoxy-Δ 12,14 -PGD 2 , PGJ 2 , Δ 12 -PGJ 2 and 15-deoxy-Δ 12,14 -PGJ 2 . ILC2 cytokine production was dose dependent as well but with an average sixfold reduced potency compared to cell migration (IL-5 range 108.1 to 526.9 nM, IL-13 range: 125.2 to 788.3 nM). Compared to PGD 2 , the absolute cytokine secretion was reduced in the presence of most metabolites. Fevipiprant dose-dependently inhibited eosinophil shape change, ILC2 migration and ILC2 cytokine secretion with (sub)-nanomolar potencies., Conclusion: Prostaglandin D 2 metabolites initiate ILC2 migration and IL-5 and IL-13 cytokine secretion in a DP 2 dependent manner. Our data indicate that metabolites may be important for in vivo eosinophil activation and ILC2 migration and to a lesser extent for ILC2 cytokine secretion., (© 2021. The Author(s).)

15-Deoxy-Δ- 12,14 -prostaglandin J2 (15d-PGJ2) is an endogenous agonist of the ligand dependent transcriptional factor, peroxisome proliferator-activated receptor -gamma (PPAR-γ). Although PPAR-γ mediates some actions of 15d-PGJ2, many actions of 15d-PGJ2 are independent of PPAR-γ. The PPAR-γ signaling pathway has beneficial effects on tumor progression, inflammation, oxidative stress, and angiogenesis in numerous studies. In this review, various studies were analyzed to understand the effects of 15d-PGJ2 in vascular smooth muscle cells (VSMC)s. 15d-PGJ2 inhibits proliferation of VSMCs during vascular remodeling and it alters the expression of contractile proteins and inflammatory components within these cells as well. However, the effects of 15d-PGJ2 as well as its ability to induce PPAR-γ activation remains controversial as contradictory effects of this prostaglandin in VSMCs exist. Understanding the mechanisms by which 15d-PGJ2 elicit beneficial actions whether by PPAR-γ activation or independently, will aid in developing new therapeutic strategies for diseases such as hypertension with an inflammatory component. Although great advances are being made, more research is needed to reach definitive conclusions., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Targeting the common molecular mechanism of type 2 diabetes mellitus and Alzheimer's disease (AD), including dysregulation of glucose metabolism, insulin resistance, and neuroinflammation, might be an efficient treatment strategy for AD. Previous studies have shown that 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), an endogenous PPARγ agonist, has anti-inflammatory, insulin sensitizing and anti-diabetic effects. However, whether 15d-PGJ2 has beneficial effects on AD remains to be elucidated. In the present study, we found that intranasal administration of 15d-PGJ2 (300 ng/30 μL/day) for 3 months significantly inhibited Aβ plaques, suppressed neuroinflammation, and attenuated cognitive deficits in APP/PS1 transgenic mice. Interestingly, 15d-PGJ2 treatment could increase brain glucose uptake, as detected by 18 F-FDG microPET imaging, and co-localization of GLUT4 and NeuN in the hippocampus of APP/PS1 mice. Furthermore, 15d-PGJ2 markedly increased the expression of PPARγ and PGC-1α, upregulated GLUT4, and decreased the phosphorylation of IRS-1 (Ser616) in the hippocampus of APP/PS1 mice. Importantly, co-administration of a PPARγ antagonist GW9662 abrogated these protective effects of 15d-PGJ2. Collectively, intranasal 15d-PGJ2 conferred protective effects against AD by activating PPARγ-dependent PGC-1α/GLUT4 signalling. The PPARγ agonist 15d-PGJ2 might be a potential therapeutic drug for AD., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The mechanism by which cyclooxygenase (COX) inhibition increases antigen-induced responses in airways remains unknown. Male albino guinea pigs were sensitized to ovalbumin (OVA). Intact rings of the trachea were isolated and mounted in organ baths for either force measurements or lipid mediator release analysis by UPLC-MS/MS or EIA following relevant pharmacological interventions. First, challenge with OVA increased the release of all primary prostanoids (prostaglandin (PG) D 2 /E 2 /F 2α /I 2 and thromboxanes). This release was eliminated by unselective COX inhibition (indomethacin) whereas selective inhibition of COX-2 (lumiracoxib) did not inhibit release of PGD 2 or thromboxanes. Additionally, the increased levels of leukotriene B 4 and E 4 after OVA were further amplified by unselective COX inhibition. Second, unselective inhibition of COX and selective inhibition of the prostaglandin D synthase (2-Phenyl-Pyrimidine-5-Carboxylic Acid (2,3-dihydro-indol-1-yl)-amide) amplified the antigen-induced bronchoconstriction which was reversed by exogenous PGD 2 . Third, a DP 1 receptor agonist (BW 245c) concentration-dependently reduced the antigen-induced constriction as well as reducing released histamine and cysteinyl-leukotrienes, a response inhibited by the DP 1 receptor antagonist (MK-524). In contrast, a DP 2 receptor agonist (15(R)-15-methyl PGD 2 ) failed to modulate the OVA-induced constriction. In the guinea pig trachea, endogenous PGD 2 is generated via COX-1 and mediates an inhibitory effect of the antigen-induced bronchoconstriction via DP 1 receptors inhibiting mast cell release of bronchoconstrictive mediators. Removal of this protective function by COX-inhibition results in increased release of mast cell mediators and enhanced bronchoconstriction., (Copyright © 2021. Published by Elsevier B.V.)

Although apoptosis of keratinocytes has been relatively well studied, there is a lack of information comparing potentially proapoptotic treatments for healthy and diseased skin cells. Psoriasis is a chronic autoimmune-mediated skin disease manifested by patches of hyperproliferative keratinocytes that do not undergo apoptosis. UVB phototherapy is commonly used to treat psoriasis, although this has undesirable side effects, and is often combined with anti-inflammatory compounds. The aim of this study was to analyze if cannabidiol (CBD), a phytocannabinoid that has anti-inflammatory and antioxidant properties, may modify the proapoptotic effects of UVB irradiation in vitro by influencing apoptotic signaling pathways in donor psoriatic and healthy human keratinocytes obtained from the skin of five volunteers in each group. While CBD alone did not have any major effects on keratinocytes, the UVB treatment activated the extrinsic apoptotic pathway, with enhanced caspase 8 expression in both healthy and psoriatic keratinocytes. However, endoplasmic reticulum (ER) stress, characterized by increased expression of caspase 2, was observed in psoriatic cells after UVB irradiation. Furthermore, decreased p-AKT expression combined with increased 15-d-PGJ 2 level and p-p38 expression was observed in psoriatic keratinocytes, which may promote both apoptosis and necrosis. Application of CBD partially attenuated these effects of UVB irradiation both in healthy and psoriatic keratinocytes, reducing the levels of 15-d-PGJ 2 , p-p38 and caspase 8 while increasing Bcl2 expression. However, CBD increased p-AKT only in UVB-treated healthy cells. Therefore, the reduction of apoptotic signaling pathways by CBD, observed mainly in healthy keratinocytes, suggests the need for further research into the possible beneficial effects of CBD.

Tramadol, a weak μ-opioid receptor (MOR) agonist with inhibitory effects on the reuptake of serotonin (5-hydroxytryptamine; 5-HT) and norepinephrine, is an effective analgesic to chronic pains. Osteoprotegerin produced by osteoblasts is essential for bone remodeling to suppress osteoclastic bone resorption. We previously reported that prostaglandin D 2 (PGD 2 ) induces osteoprotegerin synthesis whereby p44/p42 mitogen-activated protein (MAP) kinase, p38 MAP kinase and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) are involved in osteoblast-like MC3T3-E1 cells. Herein, we investigated the mechanism underlying the effect of tramadol on the PGD 2 -induced osteoprotegerin synthesis in these cells. Tramadol enhanced the PGD 2 -induced release and mRNA expression of osteoprotegerin. Naloxone, a MOR antagonist, reduced the amplification by tramadol of the PGD 2 -stimulated osteoprotegerin release. Not the selective norepinephrine reuptake inhibitor reboxetine but the selective serotonin reuptake inhibitors fluvoxamine and sertraline upregulated the PGD 2 -induced osteoprotegerin release, which was further amplified by morphine. Tramadol enhanced PGD 2 -stimulated phosphorylation of p38 MAP kinase and SAPK/JNK, but not p44/p42 MAP kinase. Both SB203580 and SP600125 suppressed the tramadol effect to enhance the PGD 2 -stimulated osteoprotegerin release. Tramadol enhanced the PGE 2 -induced osteoprotegerin release as well as PGD 2 . These results suggest that tramadol amplifies the PGD 2 -induced osteoprotegerin synthesis at the upstream of p38 MAP kinase and SAPK/JNK in the involvement of both MOR and 5-HT transporter in osteoblasts., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Lipid-metabolizing enzymes and their metabolites affect inflammation and fibrosis, but their roles in chronic kidney disease (CKD) have not been completely understood., Methods: To clarify their role in CKD, we measured the mRNA levels of major lipid-metabolizing enzymes in 5/6 nephrectomized (Nx) kidneys of C57BL/6 J mice. Mediator lipidomics was performed to reveal lipid profiles of CKD kidneys., Results: In 5/6 Nx kidneys, both mRNA and protein levels of Alox15 were higher when compared with those in sham kidneys. With respect to in situ hybridization, the mRNA level of Alox15 was higher in renal tubules of 5/6 Nx kidneys. To examine the role of Alox15 in CKD pathogenesis, we performed 5/6 Nx on Alox15 -/- mice. Alox15 -/- CKD mice exhibited better renal functions than wild-type mice. Interstitial fibrosis was also inhibited in Alox15 -/- CKD mice. Mediator lipidomics revealed that Alox15 -/- CKD mouse kidneys had significantly higher levels of PGD 2 than the control. To investigate the effects of PGD 2 on renal fibrosis, we administered PGD 2 to TGF-β1-stimulated NRK-52E cells and HK-2 cells, which lead to a dose-dependent suppression of type I collagen and αSMA in both cell lines., Conclusion: Increased PGD 2 in Alox15 -/- CKD mouse kidneys could inhibit fibrosis, thereby resulting in CKD improvement. Thus, Alox15 inhibition and PGD 2 administration may be novel therapeutic targets for CKD.

Periodontitis is a chronic inflammatory disease characterized by loss of attachment and destruction of the periodontium. Decellularized sheet, as an advanced tissue regeneration engineering biomaterial, has been researched and applied in many fields, but its effects on periodontal regeneration remain unclear. In this study, the biological properties of decellularized human periodontal ligament cell (dHPDLC) sheets were evaluated in vitro. Polycaprolactone/gelatin (PCL/GE) nanofibers were fabricated as a carrier to enhance the mechanical strength of the dHPDLC sheet. 15-deoxy-[Formula: see text]-prostaglandin J 2 (15d-PGJ 2 ) nanoparticles were added for anti-inflammation and regeneration improvement. For in vivo analysis, dHPDLC sheets combined with 15d-PGJ 2 nanoparticles, with or without PCL/GE, were implanted into rat periodontal defects. The periodontal regeneration effects were identified by microcomputed tomography (micro-CT) and histological staining, and immunohistochemistry. The results revealed that DNA content was reduced by 96.6%. The hepatocyte growth factor, vascular endothelial growth factor, and basic fibroblast growth factor were preserved but reduced. The expressions or distribution of collagen I and fibronectin were similar in dHPDLC and nondecellularized cell sheets. The dHPDLC sheets maintained the intact structure of the extracellular matrix. It could be recellularized by allogeneic human periodontal stem ligament cells and retain osteoinductive potential. Newly formed bone, cementum, and PDL were observed in dHPDLC sheets combined with 15d-PGJ 2 groups, with or without PCL/GE nanofibers, for four weeks post-operation in vivo. Bringing together all these points, this new construct of dHPDLC sheets can be a potential candidate for periodontal regeneration in an inflammatory environment of the oral cavity.

Signal transducer and activator of transcription 3 (STAT3) has been considered as a potential target for development of anticancer therapeutics. Here, we report a novel mechanism by which the cyclopentenone prostaglandin, 15-deoxy-Δ 12,14 -prostaglandin J 2 (15d-PGJ 2 ) functions as an allosteric inhibitor of STAT3. 15d-PGJ 2 inhibits phosphorylation, dimerization, nuclear translocation, and transcriptional activity of STAT3 in H-Ras-transformed human mammary epithelial cells (MCF10A-Ras) through the Michael addition reaction at cysteine 259 of STAT3. Comparative studies with 15d-PGJ 2 analogues reveal that both C12-C13 and C9-C10 double bonds conjugated to the carbonyl group in the cyclopentenone ring of 15d-PGJ 2 are essential for STAT3 binding. Antiproliferative and pro-apoptotic activities of 15d-PGJ 2 in MCF10A-Ras cells are attributable to covalent modification of STAT3 on Cys259, and mimic the effects induced by mutation of this amino acid., (© 2021 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Pharmacological agents directed to either opioid receptors or peroxisome proliferator-activated receptor gamma (PPARγ) at peripheral tissues reduce behavioral signs of persistent pain. Both receptors are expressed in muscle tissue, but the contribution of PPARγ activation to muscle pain and its modulation by opioid receptors remains unknown. To address this question, we first tested whether the endogenous PPARγ ligand 15d-PGJ2 would decrease mechanical hyperalgesia induced by carrageenan administration into the gastrocnemius muscle of rats. Next, we used receptor antagonists to determine whether the antihyperalgesic effect of 15-deoxyΔ-12,14-prostaglandin J2 (15d-PGJ2) was PPARγ- or opioid receptor-dependent. Three hours after carrageenan, muscle hyperalgesia was quantified with the Randall-Selitto test. 15d-PGJ2 prevented carrageenan-induced muscle hyperalgesia in a dose-dependent manner. The antihyperalgesic effect of 15d-PGJ2 was dose-dependently inhibited by either the PPARγ antagonist, 2-chloro-5-nitro-N-phenylbenzamide, or by the opioid receptor antagonist, naloxone. We conclude that 15d-PGJ2 targets PPARγ and opioid receptors to prevent muscle hyperalgesia. We suggest that local PPARγ receptors are important pharmacological targets for inflammatory muscle pain., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Uncontrolled macrophage functions cause failure to resolve gut inflammation and has been implicated in the pathogenesis of inflammatory bowel disease (IBD). 15-Deoxy-Δ 12,14 -prostaglandin J 2 (15d-PGJ 2 ), one of endogenous lipid mediators formed from arachidonic acid during the inflammatory process, has been reported to terminate inflammation. However, the pro-resolving effect of 15d-PGJ 2 on intestinal inflammation and underlying molecular mechanisms remain largely unknown. In the present study, we examined the effects of 15d-PGJ 2 on the resolution of dextran sulfate sodium (DSS)-induced murine colitis that mimics human IBD. Pharmacologic inhibition of prostaglandin D synthase (PGDS) responsible for the synthesis of 15d-PGJ 2 hampered resolution of inflammation in the colonic mucosa of mice treated with DSS. Notably, intraperitoneal injection of 15d-PGJ 2 accelerated the resolution of experimentally induced colitis. 15d-PGJ 2 treatment reduced the number of neutrophils and M1 macrophages, while it increased the proportion of M2 macrophages. Moreover, 15d-PGJ 2 treated mice exhibited the significantly reduced proportion of macrophages expressing the pro-inflammatory cytokine, IL-6 with concomitant suppression of STAT3 phosphorylation in the colonic mucosa of mice administered 2.5% DSS in drinking water. Taken together, these findings clearly indicate that 15d-PGJ 2 , endogenously generated from arachidonic acid by cyclooxygenase-2 and PGDS activities in inflamed tissue, promotes resolution of intestinal colitis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Kim, Jang, Zhong, Seo and Surh.)

Female fertility depends greatly on the capacity of the uterus to recognize and eliminate microbial infections, a major reason of inflammation in the endometrium in many species. This study aimed to determine the in vitro effect of peroxisome proliferator-activated receptor gamma (PPARγ) ligands on the transcriptome genes expression and alternative splicing in the porcine endometrium in the mid-luteal phase of the estrous cycle during LPS-stimulated inflammation using RNA-seq technology. The endometrial slices were incubated in vitro in the presence of LPS and PPARγ agonists-PGJ2 or pioglitazone and antagonist-T0070907. We identified 222, 3, 4, and 62 differentially expressed genes after LPS, PGJ2, pioglitazone, or T0070907 treatment, respectively. In addition, we detected differentially alternative spliced events: after treatment with LPS-78, PGJ2-60, pioglitazone-52, or T0070907-134. These results should become a basis for further studies explaining the mechanism of PPARγ action in the reproductive system in pigs., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Purpose: Thyroid eye disease (TED) is a condition that causes the tissue behind the eye to become inflamed and can result in excessive fatty tissue accumulation in the orbit. Two subpopulations of fibroblasts reside in the orbit: those that highly express Thy1 (Thy1+) and those with little or no Thy1 (Thy1-). Thy1- orbital fibroblasts (OFs) are more prone to lipid accumulation than Thy1+ OFs. The purpose of this study was to investigate the mechanisms whereby Thy1- OFs more readily accumulate lipid., Methods: We screened Thy1+ and Thy1- OFs for differences in microRNA (miRNA) expression. The effects of increasing miR-130a levels in OFs was investigated by measuring lipid accumulation and visualizing lipid deposits. To determine if adenosine monophosphate-activated protein kinase (AMPK) is important for lipid accumulation, we performed small interfering RNA (siRNA)-mediated knockdown of AMPKβ1. We measured AMPK expression and activity using immunoblotting for AMPK and AMPK target proteins., Results: We determined that miR-130a was upregulated in Thy1- OFs and that miR-130a targets two subunits of AMPK. Increasing miR-130a levels enhanced lipid accumulation and reduced expression of AMPKα and AMPKβ in OFs. Depletion of AMPK also increased lipid accumulation. Activation of AMPK using AICAR attenuated lipid accumulation and increased phosphorylation of acetyl-CoA carboxylase (ACC) in OFs., Conclusions: These data suggest that when Thy1- OFs accumulate in TED, miR-130a levels increase, leading to a decrease in AMPK activity. Decreased AMPK activity promotes lipid accumulation in TED OFs, leading to excessive fatty tissue accumulation in the orbit.

Life-threatening inflammatory conditions such as acute respiratory distress syndrome or sepsis often go hand in hand with severe vascular leakage. During inflammation, endothelial cell integrity and intact barrier function are crucial to limit leukocyte and plasma extravasation. Prostaglandin D 2 (PGD 2 ) is a potent inflammatory lipid mediator with vasoactive properties. Previous studies suggest that PGD 2 is involved in the regulation of endothelial barrier function; however, it is unclear whether this is also true for primary human pulmonary microvascular endothelial cells. Furthermore, as PGD 2 is a highly promiscuous ligand, we set out to determine which receptors are important in human pulmonary endothelial cells. In the current study, we found that PGD 2 and the DP1 agonist BW245c potently strengthened pulmonary and dermal microvascular endothelial cell barrier function and protected against thrombin-induced barrier disruption. Yet surprisingly, these effects were mediated only to a negligible extent via DP1 receptor activation. In contrast, we observed that the EP4 receptor was most important and mediated the barrier enhancement by PGD 2 and BW245c. Stimulation with PGE 2 or PGD 2 reduced AKT phosphorylation which could be reversed by prior blockade of EP4 receptors. These data demonstrate a novel mechanism by which PGD 2 may modulate inflammation and emphasizes the role of EP4 receptors in human endothelial cell function., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Natural or synthetic ligands for peroxisome proliferator-activated receptor gamma (PPAR-γ) represent an interesting tool for pharmacological interventions to treat inflammatory conditions. In particular, PPAR-γ activation prevents pain and inflammation in the temporomandibular joint (TMJ) by decreasing cytokine release and stimulating the synthesis of endogenous opioids. The goal of this study was to clarify whether PPAR-γ activation induces macrophage polarization, inhibiting inflammatory cytokine release and leukocyte recruitment. In addition, we investigated the involvement of heme oxygenase 1 (HO-1) in downstream events after PPAR-γ activation. Our results demonstrate that PPAR-γ activation ablates cytokine release by Bone Marrow-Derived Macrophages (BMDM) in vitro. 15d-PGJ 2 induces the PPAR-γ heterodimer activation from rat macrophages, with macrophage polarization from M1-like cells toward M2-like cells. This response is mediated through HO-1. PPAR-γ activation diminished neutrophil migration induced by carrageenan, which was also HO-1 dependent. Ca 2+ /calmodulin expression did not change after PPAR-γ activation indicating that is not required for the activation of the intracellular L-arginine/NO/cGMP/K +ATP channel pathway. In summary, the anti-inflammatory actions induced by PPAR-γ activation involve macrophage polarization. HO-1 expression is increased and HO-1 activity is required for the suppression of neutrophil migration., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Activation of peroxisome proliferator-activated receptor γ (PPARγ) serves as a key factor in the proliferation and invasion of breast cancer cells and is a potential therapeutic target for breast cancer. However, the mechanisms underlying this effect remain largely unknown. Heme oxygenase-1 (HO-1) is induced and overexpressed in various cancers and is associated with features of tumor aggressiveness. Recent studies have shown that HO-1 is a major downstream target of PPARγ. In this study, we investigated the effects of induction of HO-1 by PPARγ on TPAinduced MMP-9 expression and cell invasion using MCF-7 breast cancer cells. TPA treatment increased NF-κB /AP-1 DNA binding as well as MMP-9 expression. These effects were significantly blocked by 15d-PGJ2, a natural PPARγ ligand. 15d-PGJ2 induced HO-1 expression in a dose-dependent manner. Interestingly, HO-1 siRNA significantly attenuated the inhibition of TPA-induced MMP-9 protein expression and cell invasion by 15d-PGJ2. These results suggest that 15d-PGJ2 inhibits TPA-induced MMP- 9 expression and invasion of MCF-7 cells by means of a heme oxygenase-1-dependent mechanism. Therefore, PPARγ/HO-1 signaling- pathway inhibition may be beneficial for prevention and treatment of breast cancer. [BMB Reports 2020; 53(4): 212-217].

Oxidized lipids play a critical role in a variety of diseases with two faces: pro- and anti-inflammatory. The molecular mechanisms of this Janus-faced activity remain largely unknown. Here, we have identified that cyclopentenone-containing prostaglandins such as 15d-PGJ2 and structurally related oxidized phospholipid species possess a dual and opposing bioactivity in inflammation, depending on their concentration. Exposure of dendritic cells (DCs)/macrophages to low concentrations of such lipids before Toll-like receptor (TLR) stimulation instigates an anti-inflammatory response mediated by nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent inhibition of nuclear factor κB (NF-κB) activation and downstream targets. By contrast, high concentrations of such lipids upon TLR activation of DCs/macrophages result in inflammatory apoptosis characterized by mitochondrial depolarization and caspase-8-mediated interleukin (IL)-1β maturation independently of Nrf2 and the classical inflammasome pathway. These results uncover unexpected pro- and anti-inflammatory activities of physiologically relevant lipid species generated by enzymatic and non-enzymatic oxidation dependent on their concentration, a phenomenon known as hormesis., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

This study evaluated the effect of a cyclopentenone-type PG, 15-Deoxy-Δ12,14-PG J2 (15d-PGJ2), and lectin (ScLL) on the viability of human gingival fibroblasts (HGFs), and on IL-6 and TGFβ-1 release by these fibroblasts, stimulated with lipopolysaccharide (LPS). HGFs were stimulated with LPS 10 μg/ml and treated with 15d-PGJ2 1 and 2 μg/ml, and ScLL 2 and 5 μg/ml, for 1 and 3h, and then evaluated for viability by MTT assay. Supernatant was collected to detect IL-6 and TGFβ-1 release, by ELISA. Positive control was cells kept in Dulbecco's Modified Eagle's Medium, and negative control was those kept in LPS. Data were analyzed by ANOVA and Dunnett's test (α = 0.05). No significant difference was found in viability among experimental groups at 1h (p > 0.05). Percentage of ScLL 5 µg/ml viable cells was similar to that of positive control at evaluated periods (p > 0.05), whereas the other groups had lower levels than the positive control (p < 0.05). IL-6 release was statistically higher for ScLL 5 μg/ml and 15d-PGJ2 2 µg/ml at 1h, compared with the other treated groups and positive control (p < 0.05). No significant differences were found among the groups at 3h (p > 0.05), except for ScLL 2 µg/ml and 15d-PGJ2 1 µg/ml, which showed lower IL-6 release compared with that of negative control (p < 0.05). No significant difference was found among the groups for TGFβ-1 release (p > 0.05). Results indicated that ScLL 5 μg/ml did not interfere in viability, and ScLL 2 µg/ml and 15d-PGJ2 1 µg/ml demonstrated reduced IL-6 release. Tested substances had no effect on TGFβ-1 release.

Renal cell carcinoma (RCC) is one of the chemoresistant cancers. There is a pressing need to establish therapeutic approaches to prevent RCC proliferation and metastasis. The electrophilic 15-deoxy-Δ 12,14 -prostaglandin J 2 (15d-PGJ 2 ) is an endogenous anti-cancerous agent. Treatment with high concentrations of 15d-PGJ 2 is known to induce apoptosis of RCC cells, independent of the nuclear receptor, peroxisome proliferator-activated receptor-γ (PPARγ). In this study, we investigated the effects of 15d-PGJ 2 on the metastatic properties of RCC Caki-2 cells. The metastatic potential of RCC was evaluated by measuring the migratory ability of Caki-2 cells. Although treatment with low concentrations of 15d-PGJ 2 did not cause apoptosis, it did decrease the migration of Caki-2 cells in a concentration-dependent manner. PPARγ did not mediate the inhibitory effect of 15d-PGJ 2 on the migration of Caki-2 cells. Treatment with a low concentration of 15d-PGJ 2 resulted in disassembled focal adhesions and extensive filamentous actin reorganization. Furthermore, 15d-PGJ 2 significantly reduced phosphorylation of focal adhesion kinase (FAK). In conclusion, 15d-PGJ 2 attenuated the migratory ability of RCC, independent of PPARγ. Further, 15d-PGJ 2 appeared to suppress cell migration via inactivation of FAK and subsequent disassembly of focal adhesion. Our present study highlights the therapeutic potential of 15d-PGJ 2 for prevention of RCC metastasis.

The manifestation of periodontitis-related inflammatory reaction is inevitably bound to the production of prostaglandins E 2 and D 2 which have been suggested to mediate osteoclastic and osteogenic effects within the affected tissue. We demonstrated the presence of PGE 2 and PGD 2 receptors on hMSCs on RNA level and with immunofluorescence. For each Prostaglandin, three concentrations were studied: 0.1; 0.5 or 1.0 µg/ml. A lower expression of EP1 and EP4 (PGE 2 receptors 1 and 4) after stimulation with PGE 2 was shown, thus a tendency to compromise osteogenic differentiation and metabolism. PGE 2 induced a higher growth-rate during the first week, while a continuous inflammatory challenge determined a decrease of the proliferation of hMSCs. PGD 2 inhibited cell growth irrespective of the duration of the stimulation. PGE 2 and PGD 2 have also negative effects on calcium deposition osteogenic, thus on differentiation of hMSCs. PGE 2 and PGD 2 seem to induce bone resorption also having indirectly a negative impact on the osteogenic differentiation of hMSCs. Thus, inhibitors of PGE 2 and PGD 2 can be used as adjunct to mechanical periodontal treatment., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Cyclosporine A (CsA) is an immunosuppressive drug used in transplantation and treatment of autoimmune diseases. Experimental studies revealed impairments in liver function and morphology among cyclosporine-treated animals. The aim of the study was to evaluate hepatoprotective activity of peroxisome-proliferator-activated receptors γ (PPARγ) ligands: rosiglitazone and 15-deoxy-Δ 12,14 -prostaglandin J 2 (PGDJ2) on CsA-induced hepatotoxicity in experimental animals. CsA was administered subcutaneously at a dose of 15 mg/kg/day for 28 days. Both PPARγ agonists were given for 28 days 0.5 hour before the administration of CsA. Rosiglitazone was administered orally at a dose of 8 mg/kg/day and PGDJ2 was given intraperitoneally at a dose of 30 μg/kg/day. CsA induced liver injury was evidenced by increased serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and bilirubin. Concentrations of glutathione (GSH) and glutathione disulfide (GSSG), lipid peroxidation products, nicotinamide adenine dinucleotide+/nicotinamide adenine dinucleotide hydrogen (NAD + /NADH), nicotinamide adenine dinucleotide phosphate+/nicotinamide adenine dinucleotide phosphate hydrogen (NADP + /NADPH) and adenosine diphosphate/adenosine triphosphate (ADP/ATP) ratios and caspase 3 activity that were measured in the liver tissue showed, that CsA induced oxidative stress, evoked an imbalanced redox state and apoptosis in the liver. Microscope examination showed sinusoidal dilatation, mononuclear cell infiltration, necrosis of hepatocytes, intracellular vacuolar degeneration and microvesicular steatosis and apoptopic cells. The biochemical and morphological changes induced by CsA were limited by administration of both PPARγ agonist - rosiglitazone and PGDJ2. Our biochemical and liver histopathological examination indicate that both PPARγ agonists may play an important role in protecting against CsA-induced hepatotoxicity.

Since chronic inflammation is associated with the pathogenesis of atherosclerosis, inflammatory cytokines might contribute to the phenotypic modulation of vascular smooth muscle cells (VSMCs). Tumor necrosis factor α (TNFα) facilitated the transformation of contractile VSMCs to the synthetic phenotype, as determined by the expression of marker proteins and a collagen gel contraction assay. Western blot analysis and a cyclooxygenase-2 (COX2) promoter assay revealed that TNFα stimulation resulted in the induction of COX2. The overexpression, silencing, or pharmacological inhibition of COX2 significantly affected TNFα-induced phenotypic conversion, and of the tested prostaglandins, only PGD 2 significantly induced phenotypic conversion. ERK was significantly activated by PGD 2 stimulation, and the pharmacological inhibition of ERK blocked the PGD 2 -induced phenotypic conversion of VSMCs. However, antagonists or agonists of PGD 2 receptors did not affect VSMC conversion. In contrast, spontaneously dehydrated forms of PGD 2 , such as PGJ 2 , Δ 12 -PGJ 2 , and 15-d-PGJ 2 , strongly induced phenotypic conversion. A reporter gene assay showed that TNFα, PGD 2 , and 15-d-PGJ 2 significantly activated the peroxisome proliferator-responsive element (PPRE) promoter. In addition, the overexpression or silencing of peroxisome proliferator-activated receptor δ (PPARδ) significantly influenced 15-d-PGJ 2 -induced phenotypic conversion. Finally, atherosclerotic neointima formation was significantly suppressed in mice lacking TNFα. In addition, mice fed celecoxib exhibited complete inhibition of carotid artery ligation-induced neointima formation. This study shows that PGD 2 regulates the phenotypic conversion of VSMCs by generating an endogenous ligand of PPAR, and that this leads to neointima formation in occlusive arterial disease.

Heat shock protein (HSP) 90 that is ubiquitously expressed in various tissues is a major molecular chaperone. We have previously demonstrated that prostaglandin D 2 (PGD 2 ), a bone remodeling factor, elicits the expression of HSP27, a small HSP, through stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) and p38 mitogen-activated protein (MAP) kinase in osteoblast-like MC3T3-E1 cells. In the present study, we investigated the involvement of HSP90 in the PGD 2 -stimulated HSP27 induction and the underlying mechanism in MC3T3-E1 cells. Onalespib, an inhibitor of HSP90, significantly enhanced the PGD 2 -stimulated HSP27 induction. In addition, geldanamycin, another HSP90 inhibitor, potentiated the HSP27 induction. Both onalespib and geldanamycin markedly amplified the PGD 2 -induced phosphorylation of SAPK/JNK and p38 MAP kinase. SP600125, an inhibitor of SAPK/JNK, and SB203580, an inhibitor of p38 MAP kinase, suppressed the amplification by onalespib of the PGD 2 -stimulated HSP27 induction. These results strongly suggest that HSP90 plays a negative role in the HSP27 induction stimulated by PGD 2 in osteoblasts, and that the inhibitory effect of HSP90 is mediated through the regulation of SAPK/JNK and p38 MAP kinase., (Copyright © 2019. Published by Elsevier Inc.)

Background/aims: Synovial fibrosis is a pathological process that is observed in several musculoskeletal disorders and characterized by the excessive deposition of extracellular matrix, as well as cell migration and proliferation. Despite the fact that glucocorticoids are widely employed in the treatment of rheumatic pathologies such as osteoarthritis (OA) and rheumatoid arthritis, the mechanisms by which glucocorticoids act in the joint and their impacts on pro-fibrotic pathways are still unclear., Materials: Human OA synovial fibroblasts were obtained from knee and hip joints. Cells were treated with prednisolone (1 mM) or transforming growth factor-beta 1 (TGF-β1) (10 ng/ml) for 1 and 7 days for quantification of RNA and protein expression (by real-time quantitative reverse transcription-PCR and western blot, respectively), 72 h for immunocytochemistry analysis, and 48 h for proliferation (by BrdU assay) and migration (by wound assay) studies. In addition, cells were preincubated with prednisolone and/or the peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist 15-deoxy-Δ-12,14-prostaglandin J2 (15d-PGJ2) for 6 h before adding TGF-β1. pSmad1/5, pSmad2 and β-catenin levels were analyzed by Western blot. The activin receptor-like kinase-5 (ALK-5) inhibitor (SB-431542) was employed for the mechanistic assays., Results: Prednisolone showed a predominant anti-fibrotic impact on fibroblast-like synoviocytes as it attenuated the spontaneous and TGF-β-induced gene expression of pro-fibrotic markers. Prednisolone also reduced α-sma protein and type III collagen levels, as well as cell proliferation and migration after TGF-β stimulation. However, prednisolone did not downregulate the gene expression of all the pro-fibrotic markers tested and did not restore the reduced PPAR-γ levels after TGF-β stimulation. Interestingly, anti-fibrotic actions of the glucocorticoid were reinforced in the presence of the PPAR-γ agonist 15d-PGJ2. Combined pretreatment modulated Smad2/3 levels and, similar to the ALK-5 inhibitor, blocked β-catenin accumulation elicited by TGF-β., Conclusions: Prednisolone, along with 15d-PGJ2, modulates pro-fibrotic pathways activated by TGF-β in synovial fibroblasts at least partially through the inhibition of ALK5/Smad2 signaling and subsequent β-catenin accumulation. These findings shed light on the potential therapeutic effects of glucocorticoids treatment combined with a PPAR-γ agonist against synovial fibrosis, although future studies are warranted to further evaluate this concern., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Although prostaglandins (PGs) are known to be involved in the progression of arthritis, the role of PGD 2 remains unclear. In this study, we evaluated the role of PGD 2 in joint inflammation using genetically modified mice. Injection of complete Freund's adjuvant (CFA) increased the production of PGD 2 and induced paw swelling and cartilage erosion in wild-type (WT) mice. These phenomena were accompanied with an increase in the mRNA levels of TNF-α, IL-6, IL-1β, and matrix-degrading metalloproteinase-9. Knockdown of hematopoietic PGD synthase (H-PGDS) abolished the PGD 2 production and exacerbated all of the arthritic manifestations in the inflamed paw. Immunostaining revealed that infiltrating macrophages strongly expressed H-PGDS in the CFA-injected paw. Morphologic studies revealed vascular hyperpermeability and angiogenesis in the inflamed WT paw. H-PGDS deficiency was accelerated, whereas daily administration of a PGD 2 receptor D prostanoid (DP) agonist attenuated the CFA-induced hyperpermeability and angiogenesis. We further confirmed that DP deficiency exacerbated, whereas the administration of the DP agonist improved, the CFA-induced arthritic manifestations. The findings demonstrate that H-PGDS-derived PGD 2 ameliorates joint inflammation by attenuating vascular permeability and subsequent angiogenesis and indicates the therapeutic potential of a DP agonist for arthritis.-Tsubosaka, Y., Maehara, T., Imai, D., Nakamura, T., Kobayashi, K., Nagata, N., Fujii, W., Murata, T. Hematopoietic prostaglandin D synthase-derived prostaglandin D 2 ameliorates adjuvant-induced joint inflammation in mice.

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.

Mitochondrial impairment and calcium (Ca ++ ) dyshomeostasis are associated with Parkinson's disease (PD). When intracellular ATP levels are lowered, Ca ++ -ATPase pumps are impaired causing cytoplasmic Ca ++ to be elevated and calpain activation. Little is known about the effect of calpain activation on Parkin integrity. To address this gap, we examined the effects of mitochondrial inhibitors [oligomycin (Oligo), antimycin and rotenone] on endogenous Parkin integrity in rat midbrain and cerebral cortical cultures. All drugs induced calpain-cleavage of Parkin to ~36.9/43.6 kDa fragments. In contrast, treatment with the proinflammatory prostaglandin J2 (PGJ2) and the proteasome inhibitor epoxomicin induced caspase-cleavage of Parkin to fragments of a different size, previously shown by others to be triggered by apoptosis. Calpain-cleaved Parkin was enriched in neuronal mitochondrial fractions. Pre-treatment with the phosphatase inhibitor okadaic acid prior to Oligo-treatment, stabilized full-length Parkin phosphorylated at Ser 65 , and reduced calpain-cleavage of Parkin. Treatment with the Ca ++ ionophore A23187, which facilitates Ca ++ transport across the plasma membrane, mimicked the effect of Oligo by inducing calpain-cleavage of Parkin. Removing extracellular Ca ++ from the media prevented oligomycin- and ionophore-induced calpain-cleavage of Parkin. Computational analysis predicted that calpain-cleavage of Parkin liberates its UbL domain. The phosphagen cyclocreatine moderately mitigated Parkin cleavage by calpain. Moreover, the pituitary adenylate cyclase activating peptide (PACAP27), which stimulates cAMP production, prevented caspase but not calpain-cleavage of Parkin. Overall, our data support a link between Parkin phosphorylation and its cleavage by calpain. This mechanism reflects the impact of mitochondrial impairment and Ca ++ -dyshomeostasis on Parkin integrity and could influence PD pathogenesis., (Copyright © 2019 Elsevier B.V. All rights reserved.)