Prostaglandins & Other Lipid Mediators

A novel mPGES-1 inhibitor alleviates inflammatory responses by downregulating PGE2 in experimental models Publication date: October 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 144 Author(s): Hwi-Ho Lee, YoonHyoung Moon, Ji-Sun Shin, Jeong-Hun Lee, Tae-Woo Kim, Changyoung Jang, Changmin Park, Juhee Lee, Younghoon Kim, Younggwan Kim, Oliver Werz, Boyoung Y. Park, Jae Yeol Lee, Kyung-Tae Lee Abstract We previously reported the strong inhibitory potency of N-phenyl-N'-(4- benzyloxyphenoxycarbonyl)-4-chlorophenylsulfonyl hydrazide (PBCH) on lipopolysaccharide (LPS)-induced prostaglandin E2 (PGE2) production in macrophages. Herein, we characterized PBCH as a microsomal prostaglandin E synthase-1 (mPGES-1) inhibitor and evaluated its anti-inflammatory effects using in vivo experimental models. PBCH inhibited PGE2production in various activated cells in addition to inhibiting the mPGES-1 activity. In the ear edema and paw edema rat models, PBCH significantly reduced ear thickness and paw swelling, respectively. Besides, in adjuvant-induced arthritis (AIA) rat model, PBCH decreased paw swelling, plasma rheumatoid factor (RF), and receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) ratio. Furthermore, while PBCH reduced the plasma prostaglandin E metabolite (PGEM) levels, it did not affect the plasma levels of prostacyclin (PGI2) and thromboxane A2 (TXA2). Our data suggest that PBCH downregulates PGE2 production by interfering with the mPGES-1 activity, thus reducing edema and arthritis in rat models. Graphical abstract

Prostaglandin E2 and an EP4 receptor agonist inhibit LPS-Induced monocyte chemotactic protein 5 production and secretion in mouse cardiac fibroblasts via Akt and NF-κB signaling Publication date: October 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 144 Author(s): Timothy D. Bryson, Jacob Ross, Edward Peterson, Pamela Harding Abstract Background Prostaglandin E2 (PGE2) signals through 4 separate G-protein coupled receptor sub-types to elicit a variety of physiologic and pathophysiological effects. We have previously reported that mice lacking the EP4 receptor in the cardiomyocytes develop heart failure with a phenotype of dilated cardiomyopathy. Also, these mice have increased levels of chemokines, like MCP-5, in their left ventricles. We have recently reported that overexpression of the EP4 receptor could improve cardiac function in the myocardial infarction model. Furthermore, we showed that overexpression of EP4 had an anti-inflammatory effect in the whole left ventricle. It has also been shown that PGE2 can antagonize lipopolysaccharide-induced secretion of chemokines/cytokines in various cell types. We therefore hypothesized that PGE2 inhibits lipopolysaccharide (LPS)-induced MCP-5 secretion in adult mouse cardiac fibroblasts via its EP4 receptor. Methods and results Our hypothesis was tested using isolated mouse adult ventricular fibroblasts (AVF) treated with LPS. Pre-treatment of the cells with PGE2 and the EP4 agonist CAY10598 resulted in reductions of the pro-inflammatory response induced by LPS. Specifically, we observed reductions in MCP-5 secretion. Western blot analysis showed reductions in phosphorylated Akt and IκBα indicating reduced NF-κB activation. The anti-inflammatory effects of PGE2 and EP4 agonist signaling appeared to be independent of cAMP, p-44/42, or p38 pathways. Conclusion Exogenous treatment of PGE2 and the EP4 receptor agonist blocked the pro-inflammatory actions of LPS. Mechanistically, this was mediated via reduced Akt phosphorylation and inhibition of NF-κB.

Enhancement by HSP90 inhibitor of PGD2-stimulated HSP27 induction in osteoblasts: Suppression of SAPK/JNK and p38 MAP kinase Publication date: August 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 143 Author(s): Woo Kim, Haruhiko Tokuda, Tetsu Kawabata, Kazuhiko Fujita, Go Sakai, Daiki Nakashima, Junko Tachi, Gen Kuroyanagi, Rie Matsushima-Nishiwaki, Kumiko Tanabe, Takanobu Otsuka, Hiroki Iida, Osamu Kozawa Abstract Heat shock protein (HSP) 90 that is ubiquitously expressed in various tissues is a major molecular chaperone. We have previously demonstrated that prostaglandin D2 (PGD2), 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 PGD2-stimulated HSP27 induction and the underlying mechanism in MC3T3-E1 cells. Onalespib, an inhibitor of HSP90, significantly enhanced the PGD2-stimulated HSP27 induction. In addition, geldanamycin, another HSP90 inhibitor, potentiated the HSP27 induction. Both onalespib and geldanamycin markedly amplified the PGD2-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 PGD2-stimulated HSP27 induction. These results strongly suggest that HSP90 plays a negative role in the HSP27 induction stimulated by PGD2 in osteoblasts, and that the inhibitory effect of HSP90 is mediated through the regulation of SAPK/JNK and p38 MAP kinase.

mPGES-1 as a new target to overcome acquired resistance to gefitinib in non-small cell lung cancer cell lines Publication date: August 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 143 Author(s): Erika Terzuoli, Filomena Costanza, Valerio Ciccone, Marina Ziche, Lucia Morbidelli, Sandra Donnini Abstract Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) as gefitinib are standard treatment of non-small cell lung cancer (NSCLC), but resistance often occurs. This study demonstrates that NSCLC cells resistant to gefitinib (GR cells) displayed a significantly higher microsomal prostaglandin E synthase-1 (mPGES-1) expression and activity than parental cells. Overexpression of mPGES-1/prostaglandin E-2 (PGE-2) signaling in GR cells was associated with acquisition of mesenchymal and stem-like cell properties, nuclear EGFR translocation and tolerance to cisplatin. mPGES-1 inhibition reduced mesenchymal and stem-like properties, and nuclear EGFR translocation in GR cells. Consistently, inhibition of mPGES-1 activity enhanced sensitivity to cisplatin and responsiveness to gefitinib in GR cells. We propose the mPGES-1/PGE-2 signaling as a potential target for treating aggressive and resistant lung cancers.

Seasonal expressions of COX-1, COX-2 and EP4 in the uteri of the wild Daurian ground squirrels (Spermophilus dauricus) Publication date: August 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 143 Author(s): Yu Wang, Yuchen Yao, Chunjiao Zhang, Yuanyuan Guo, Haolin Zhang, Yingying Han, Zhengrong Yuan, Qiang Weng Abstract Prostaglandins (PGs) play a pivotal role in uterine reproductive process including maternal recognition of pregnancy, cell proliferation, and myometrium contractions in mammals. In this study, we investigated the immunolocalizations and expression levels of Prostaglandin E2 synthases cyclo-oxygenase (COX)-1 and COX-2, as well as one of PGE2 receptor subtypes 4 (EP4) in the uteri of the wild Daurian ground squirrels (Spermophilus dauricus) during the breeding and non-breeding seasons. Histologically, the thickness of endometrium: myometrium ratio in the uteri of the breeding season was higher than that of the non-breeding season. The immunostainings of COX-1, COX-2 and EP4 were observed in stromal cells, glandular cells and myometrium cells in the breeding and non-breeding seasons. The protein and mRNA expression levels of COX-1, COX-2 and EP4 were higher in the uteri of the breeding season than those of in the non-breeding season. The mean mRNA levels of COX-1, COX-2 and EP4 were positively correlated with uterine weights. In addition, the PGE2 concentration of uterine tissues as well as plasma PGE2, 17β-estradiol, progesterone, LH and FSH levels were also significantly higher in the breeding season compared to those of the non-breeding season. These results suggested that PGE2 might play an important autocrine or paracrine role in the regulation of seasonal changes in the uterine functions of the wild Daurian ground squirrels during the breeding and non-breeding seasons.

Formyl-peptide receptor 2 suppresses proliferation, migration and invasion in human extravillous trophoblastic cells Publication date: August 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 143 Author(s): Shenzhi Zhao, Tingting Liao, Tong Zhou, Xianping Huang, Huiqiu Xiang, Jiajia Chen, Zhangye Xu Abstract Although FPR2 receptor is distributed in the endometrium and placenta, its function in human extravillous trophoblastic (TEV-1) cells still remains enigmatic. In this study, overexpression of FPR2 was performed in TEV-1 cells. Then, CCK8 transwell and wound healing assays were used to assess the cell proliferation, migration and invasion, respectively. The results showed that FPR2 overexpression significantly inhibited proliferation, invasion and migration in TEV-1 cells. In addition, FPR2 overexpression significantly decreased mRNA and protein levels of integrin-linked kinase (ILK), nuclear factor-kappa B (NF--κB), matrix metalloproteinase 9 (MMP9) and vascular endothelial growth factor (VEGF) in TEV-1 cells. These findings indicated that FPR2 overexpression alters proliferation, migration and invasion in human extravillous trophoblastic cellsthrough the ILK/NF-κB signaling pathway; ideal FPR2 levels are important for TEV-1 cells functions.

Respective contribution of cytosolic phospholipase A2α and secreted phospholipase A2 IIA to inflammation and eicosanoid production in arthritis Publication date: August 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 143 Author(s): Anne-Claire Duchez, Luc H. Boudreau, Gajendra S. Naika, Matthieu Rousseau, Nathalie Cloutier, Tania Levesque, Michael H. Gelb, Eric Boilard Abstract Phospholipase A2s (PLA2) play a key role in generation of eicosanoids. Cytosolic PLA2α (cPLA2α) is constitutively expressed in most cells, whereas IIA secreted PLA2 (sPLA2-IIA) is induced during inflammation and is present at high levels in the synovial fluid of rheumatoid arthritis patients. In mice, both cPLA2α and sPLA2-IIA have been implicated in autoimmune arthritis; however, the respective contribution of these two enzymes to the pathogenesis and production of eicosanoids is unknown. We evaluated the respective role of cPLA2α and sPLA2-IIA with regard to arthritis and eicosanoid profile in an in vivo model of arthritis. While arthritis was most severe in mice expressing both enzymes, it was abolished when both cPLA2α and sPLA2-IIA were lacking. cPLA2α played a dominant role in the severity of arthritis, although sPLA2-IIA sufficed to significantly contribute to the disease. Several eicosanoids were modulated during the course of arthritis and numerous species involved sPLA2-IIA expression. This study confirms the critical role of PLA2s in arthritis and unveils the distinct contribution of cPLA2α and sPLA2-IIA to the eicosanoid profile in arthritis.

Do arachidonic acid metabolites affect apoptosis in bovine endometrial cells with silenced PPAR genes? Publication date: August 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 143 Author(s): A.A. Szczepańska, M. Łupicka, A.J. Korzekwa Abstract Peroxisome proliferator-activated receptors (PPARs) are expressed in bovine uterus, and their agonists are arachidonic acid (AA) metabolites. We hypothesised that silencing of PPAR genes in bovine endometrial stromal cells (ESC) would change the intracellular signalling through PPAR and affect apoptosis after cell treatment with different AA metabolites. The study's aims are detection of apoptosis and examining the influence of prostaglandins and leukotrienes on apoptosis occurring in physiological ESC and cells with silenced PPAR (α, δ, and γ) genes. Silencing the PPARα and PPARδ genes in cells resulted in increased DNA fragmentation and mRNA and protein expression of caspase (CASP) -3 and -8 (P < 0.05). Neither DNA fragmentation nor the mRNA and protein expression of CASP3 and -8 in cells with silenced PPARγ gene were changed compared to physiological cells (P > 0.05). Among PPARs, PPARα and PPARδ appear to inhibit apoptosis, and AA metabolites, as PPAR agonists, modify this process in bovine ESC.

Emerging class of omega-3 fatty acid endocannabinoids & their derivatives Publication date: August 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 143 Author(s): Josephine E. Watson, Justin S. Kim, Aditi Das Abstract Cannabinoid receptor activation is involved in homeostatic regulation of the body. These receptors are activated by cannabinoids, that include the active constituents of Cannabis sativa, as well as endocannabinoids (eCBs). The eCBs are endogenously synthesized from the omega-6 and omega-3 polyunsaturated fatty acids (PUFAs). The consumption of omega-3 fatty acids shifts the balance towards a higher proportion of omega-3 eCBs, whose physiological functions warrants further investigation. Herein, we review the discovery of omega-3 fatty acid derived eCBs that are generated from long chain omega-3 PUFAs - docosahexaenoyl ethanolamide (DHA-EA or synaptamide), docosahexanoyl-glycerol (DHG), eicosapentaenoyl ethanolamide (EPA-EA) and eicosapentanoylglycerol (EPG). Furthermore, we outline the lesser known omega-3 eCB-like molecules that arise from the conjugation of omega-3 fatty acids with neurotransmitters serotonin and dopamine - DHA-serotonin (DHA-5HT), DHA-dopamine (DHA-DA), EPA-serotonin (EPA-5HT) and EPA-dopamine (EPA-DA). Additionally, we describe the role of omega-3 eCBs and their derivatives in different disease states, such as pain, inflammation and cancer. Moreover, we detail the formation and potential physiological roles of the oxidative metabolites that arise from the metabolism of omega-3 eCBs by eicosanoid synthesizing enzymes - cyclooxygenase (COX), lipoxygenase (LOX) and cytochrome P450 epoxygenase (CYP450). In summary, we outline the novel findings regarding a growing class of signaling molecules that can control the physiological and pathophysiological processes in the body.

PGE2 in fibrosis and cancer: Insights into fibroblast activation Publication date: August 2019 Source: Prostaglandins & Other Lipid Mediators, Volume 143 Author(s): Eiman Elwakeel, Bernhard Brüne, Andreas Weigert Abstract Fibroblasts are the essential cellular architects of connective tissue and as such are crucial cells in contributing to organ homeostasis. While fulfilling important repair functions during tissue regeneration upon wounding, chronic fibroblast activation provokes pathological organ fibrosis and promotes neoplastic disease progression. Identifying targets that may serve to therapeutically terminate fibroblast activation is therefore desirable. Among the mediators that may be relevant in this context is the prostanoid prostaglandin E2 (PGE2) that is produced during inflammatory settings, where pathological fibrosis occurs. Here, we summarize current, in part controversial, concepts on the impact of PGE2 on fibroblast activation in fibrotic diseases including cancer, and discuss these findings in the context of the evolving concept of fibroblast heterogeneity.

Alexandros Sfakianakis
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