Biocomputational screening of natural compounds targeting 15-hydroxyprostaglandin dehydrogenase to improve skeletal muscle during aging.

Skeletal muscle (SM) contains a diverse population of muscle stem (or satellite) cells, which are essential for the maintenance of muscle tissue and positively regulated by prostaglandin E2 (PGE2). However, in aged SM, PGE2 levels are reduced due to increased prostaglandin catabolism by 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a negative regulator of SM tissue repair and regeneration. Screening of a library of 80,617 natural compounds in the ZINC database against 15-PGDH was conducted from PyRx. Further, drug-likeness rules, including those of Lipinski, Ghose, Veber, Egan, and Muegge were performed. The selected complex was forwarded for MD simulations up to 100ns. Based on free energy of binding obtained from docking revealed that ZINC14557836 and ZINC14638400 more potently inhibiting to 15-PGDH than SW033291 (the control and high-affinity inhibitor of 15-PGDH). The free energies of binding obtained from PyRx for 15-PGDH-ZINC14557836, 15-PGDH-ZINC14638400, and 15-PGDH-SW033291 complexes were - 10.30, -9.80, and - 8.0 kcal/mol, respectively. Root mean square deviations (RMSDs), root mean square fluctuations (RMSFs), radii of gyration (Rg), solvent-accessible surface areas (SASAs), and H-bond parameters obtained by 100 ns MD simulations predicted ZINC14557836 and ZINC14638400 more stably complexed with 15-PGDH than SW033291. The several parameters, including physicochemical properties and drug-likenesses, were within acceptable limits, and ZINC14557836 and ZINC14638400 also satisfied other drug-likeness rules, including those of Lipinski, Ghose, Veber, Egan, and Muegge. These findings suggest that ZINC14557836 and ZINC14638400 provide starting points for the development of medications that increase SM regeneration and muscle stem (or satellite) cell numbers by inhibiting 15-PGDH.

Dietary Walnuts Prevented Indomethacin-Induced Gastric Damage via AP-1 Transcribed 15-PGDH, Nrf2-Mediated HO-1, and n-3 PUFA-Derived Resolvin E1.

Non-steroidal anti-inflammatory drugs (NSAIDs), the most highly prescribed drugs in the world for the treatment of pain, inflammation, and fever, cause gastric mucosal damage, including ulcers, directly or indirectly, by which the development of GI-safer (-sparing) NSAIDs relates to unmet medical needs. This study aimed to document the preventive effects of walnut polyphenol extracts (WPEs) against NSAID-induced gastric damage along with the molecular mechanisms. RGM-1 gastric mucosal cells were administered with indomethacin, and the expressions of the inflammatory mediators between indomethacin alone or a combination with WPEs were compared. The expressions of the inflammatory mediators, including COX-1 and COX-2, prostaglandin E2, 15-hydroxyprostaglandin dehydrogenase (15-PGDH), and antioxidant capacity, were analyzed by Western blot analysis, RT-PCR, and ELISA, respectively. HO-1, Nrf-2, and keap1 were investigated. The in vivo animal models were followed with in vitro investigations. The NSAIDs increased the expression of COX-2 and decreased COX-1 and 15-PGDH, but the WPEs significantly attenuated the NSAID-induced COX-2 expression. Interestingly, the WPEs induced the expression of 15-PGDH. By using the deletion constructs of the 15-PGDH promoter, we found that c-Jun is the most essential determinant of the WPE-induced up-regulation of 15-PGDH expression. We confirmed that the knockdown of c-Jun abolished the ability of the WPEs to up-regulate the 15-PGDH expression. In addition, the WPEs significantly increased the HO-1 expression. The WPEs increased the nuclear translocation of Nrf2 by Keap-1 degradation, and silencing Nrf2 markedly reduced the WPE-induced HO-1 expression. We found that the WPE-induced HO-1 up-regulation was attenuated in the cells harboring the mutant Keap1, in which the cysteine 151 residue was replaced by serine. These in vitro findings were exactly validated in indomethacin-induced gastric rat models. Daily walnut intake can be a promising nutritional supplement providing potent anti-inflammatory, antioxidative, and mucosa-protective effects against NSAID-induced GI damage.

The Enzyme 15-Hydroxyprostaglandin Dehydrogenase Inhibits a Shift to the Mesenchymal Pattern of Trophoblasts and Decidual Stromal Cells Accompanied by Prostaglandin Transporter in Preeclampsia.

Preeclampsia (PE) is a pregnancy complication beginning after 20 weeks of pregnancy that involves high blood pressure (systolic > 140 mmHg or diastolic > 90 mmHg), with or without proteinuria. Insufficient trophoblast invasion and abnormal decidualization are involved in PE development. However, whether unhealthy placenta and decidua have the same biological activities is unclear. The enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH; encoded by HPGD) degrades prostaglandin, and prostaglandin transporter (PGT), as a candidate molecule of prostaglandin carriers, helps transport prostaglandin into cells. Whether 15-PGDH and PGT are involved in PE has not been researched. In this study, we investigated the shared pathogenesis of foetal placenta and maternal decidua from the perspective of epithelial-mesenchymal transition (EMT)/mesenchymal-epithelial transition (MET) and explored the combined effects of 15-PGDH and PGT on the EMT/MET of trophoblasts and decidual stromal cells (DSCs). Here, we demonstrated that placental development and decidualization both involved EMT/MET. In PE, both trophoblasts and DSCs show more epithelial patterns. Moreover, 15-PGDH expression was downregulated in the placentas but upregulated in the deciduas of PE patients. Inhibiting 15-PGDH promotes a shift to a mesenchymal pattern of trophoblasts and DSCs depending on the PGT-mediated transport of prostaglandin E2 (PGE2). In conclusion, our results showed that inhibiting 15-PGDH promotes a shift to the mesenchymal pattern of trophoblasts and DSCs and may provide a new and alternative therapy for the treatment of PE.

Assessment of hepatic prostaglandin E2 level in carbamazepine induced liver injury.

Objective. Carbamazepine (CBZ), a widely used antiepileptic drug, is one major cause of the idiosyncratic liver injury along with immune reactions. Conversely, prostaglandin E2 (PGE2) demonstrates a hepatoprotective effect by regulating immune reactions and promoting liver repair in various types of liver injury. However, the amount of hepatic PGE2 during CBZ-induced liver injury remains elusive. In this study, we aimed to evaluate the hepatic PGE2 levels during CBZ-induced liver injury using a mouse model. Methods. Mice were orally administered with CBZ at a dose of 400 mg/kg for 4 days, and 800 mg/kg on the 5th day. Results. Plasma alanine transaminase (ALT) level increased in some of mice 24 h after the last CBZ administration. Although median value of hepatic PGE2 amount in the CBZ-treated mice showed same extent as vehicle-treated control mice, it exhibited significant elevated level in mice with severe liver injury presented by a plasma ALT level >1000 IU/L. According to these results, mice had a plasma ALT level >1000 IU/L were defined as responders and the others as non-responders in this study. Even though, the hepatic PGE2 levels increased in responders, the hepatic expression and enzyme activity related to PGE2 production were not upregulated when compared with vehicle-treated control mice. However, the hepatic 15-hydroxyprostaglandin dehydrogenase (15-PGDH) expression and activity decreased significantly in responders when compared with control mice. Conclusions. These results indicate that elevated hepatic PGE2 levels can be attributed to the downregulation of 15-PGDH expression under CBZ-induced liver injury.

Regulation of PGE2 Pathway During Cerebral Ischemia Reperfusion Injury in Rat.

Stroke is an acute central nervous system disease with high morbidity and mortality rate. Cerebral ischemia reperfusion (I/R) injury is easily induced during the development or treatment of stroke and subsequently leads to more serious brain damage. Prostaglandin E2 (PGE2) is one of the most important inflammatory mediators in the brain and contributes to both physiological and pathophysiological functions. It may be upregulated and subsequently plays a key role in cerebral ischemia reperfusion injury. The synthesis and degradation of PGE2 is an extremely complex process, with multiple key stages and molecules. However, there are few comprehensive and systematic studies conducted to investigate the synthesis and degradation of PGE2 during cerebral I/R injury, which is what we want to demonstrate. In this study, qRT-PCR and immunoblotting demonstrated that the key enzymes in PGE2 synthesis, including COX-1, COX-2, mPGES-1 and mPGES-2, were upregulated during cerebral I/R injury, but 15-PGDH, the main PGE2 degradation enzyme, was downregulated. In addition, two of PGE2 receptors, EP3 and EP4, were also increased. Meanwhile, immunohistochemistry demonstrated the localization of these molecules in ischemic areas, including cortex, striatum and hippocampus, and reflected their expression patterns in different regions. Combining the results of PCR, Western blotting and immunohistochemistry, we can determine where the increase or decrease of these molecules occurs. Overall, these results further indicate a possible pathway that mediates enhanced production of PGE2, and thus that may impact production of inflammatory cytokines including IL-1ß and TNF-α during cerebral I/R injury.

15-Hydroxyprostaglandin dehydrogenase inhibitor prevents contrast-induced acute kidney injury.

The two primary mechanisms by which iodinated contrast media (CM) causes contrast-induced acute kidney injury (CIAKI) are the hemodynamic effect causing intrarenal vasoconstriction and the tubular toxic effect causing acute tubular necrosis. Inhibition of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), which degrades prostaglandin E2 (PGE2), promotes tissue repair and regeneration in many organs. PGE2 causes intrarenal arterial vasodilation. In this study, we investigated whether a 15-PGDH inhibitor can act as a candidate for blocking these two major mechanisms of CIAKI. We established a CIAKI mouse model by injecting a 10 gram of iodine per body weight (gI/kg) dose of iodixanol into each mouse tail vein. A 15-PGDH inhibitor (SW033291), PGE1, or PGE2 were administered to compare the renal functional parameters, histologic injury, vasoconstriction, and renal blood flow changes. In addition, human renal proximal tubular epithelial cells were cultured in a CM-treated medium. SW033291, PGE1, or PGE2 were added to compare any changes in cell viability and apoptosis rate. CIAKI mice that received SW033291 had lower serum levels of creatinine, neutrophil gelatinase-associated lipocalin, and kidney injury molecule 1 (p < 0.001); lower histologic injury score and TUNEL positive rates (p < 0.001); and higher medullary arteriolar area (p < 0.05) and renal blood flow (p < 0.001) than CM + vehicle group. In cell culture experiments, Adding SW033291 increased the viability rate (p < 0.05) and decreased the apoptosis rate of the tubular epithelial cells (p < 0.001). This 15-PGDH inhibitor blocks the two primary mechanisms of CIAKI, intrarenal vasoconstriction and tubular cell toxicity, and thus has the potential to be a novel prophylaxis for CIAKI. Abbreviations: 15-PGDH: 15-hydroxyprostaglandin dehydrogenase; AMP: adenosine monophosphate; CIAKI: contrast-induced acute kidney injury; CM: contrast media; EP: prostaglandin E2 receptor; hRPTECs: human-derived renal proximal tubule epithelial cells; KIM-1: kidney injury molecule-1; MTT: 3-(4,5-Dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide; NGAL: neutrophil gelatinase-associated lipocalin; PBS: phosphate-buffered saline; PGE1: prostaglandin E1; PGE2: prostaglandin E2; RBF: renal blood flow; TUNEL: terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling; α-SMA: α-Smooth muscle actin.

Inhibiting eicosanoid degradation exerts antifibrotic effects in a pulmonary fibrosis mouse model and human tissue.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a disease with high 5-year mortality and few therapeutic options. Prostaglandin (PG) E2 exhibits antifibrotic properties and is reduced in bronchoalveolar lavage from patients with IPF. 15-Prostaglandin dehydrogenase (15-PGDH) is the key enzyme in PGE2 metabolism under the control of TGF-ß and microRNA 218. OBJECTIVE: We sought to investigate the expression of 15-PGDH in IPF and the therapeutic potential of a specific inhibitor of this enzyme in a mouse model and human tissue. METHODS: In vitro studies, including fibrocyte differentiation, regulation of 15-PGDH, RT-PCR, and Western blot, were performed using peripheral blood from healthy donors and patients with IPF and A549 cells. Immunohistochemistry, immunofluorescence, 15-PGDH activity assays, and in situ hybridization as well as ex vivo IPF tissue culture experiments were done using healthy donor and IPF lungs. Therapeutic effects of 15-PGDH inhibition were studied in the bleomycin mouse model of pulmonary fibrosis. RESULTS: We demonstrate that 15-PGDH shows areas of increased expression in patients with IPF. Inhibition of this enzyme increases PGE2 levels and reduces collagen production in IPF precision cut lung slices and in the bleomycin model. Inhibitor-treated mice show amelioration of lung function, decreased alveolar epithelial cell apoptosis, and fibroblast proliferation. Pulmonary fibrocyte accumulation is also decreased by inhibitor treatment in mice, similar to PGE2 that inhibits fibrocyte differentiation from blood of healthy donors and patients with IPF. Finally, microRNA 218-5p, which is downregulated in patients with IPF, suppressed 15-PGDH expression in vivo and in vitro. CONCLUSIONS: These findings highlight the role of 15-PGDH in IPF and suggest 15-PGDH inhibition as a promising therapeutic approach.

PGE2 deficiency predisposes to anaphylaxis by causing mast cell hyperresponsiveness.

BACKGROUND: Reduced levels of prostaglandin E2 (PGE2) contribute to aspirin-induced hypersensitivity. COX inhibitors are also frequent cofactors in anaphylaxis. Whether alterations in the PGE2 system contribute to anaphylaxis independently of COX inhibitor intake is unclear. OBJECTIVE: Our aim was to test the hypothesis that relative PGE2 deficiency predisposes to anaphylaxis. METHODS: Sera from 48 patients with anaphylaxis and 27 healthy subjects were analyzed for PGE2 levels and correlated against severity; 9α,11ß-PGF2 and PGI2 metabolites were measured for control purposes. PGE2 stabilization by 15-hydroxyprostaglandin dehydrogenase inhibitor or EP2 or EP4 receptor agonists were used in a murine model of passive systemic anaphylaxis. FcεRI-triggered mediator release was determined in bone marrow-derived cultured mast cells (MCs) and human skin-derived MCs. Signaling was studied by Western blot analysis. RESULTS: Patients with anaphylaxis were characterized by markedly reduced PGE2 levels vis-à-vis healthy subjects, whereas prostacyclin metabolite levels were diminished only weakly, and 9α,11ß-PGF2 levels conversely increased. PGE2 was negatively correlated with severity. Lower PGE2 levels and higher susceptibility to anaphylaxis were also found in C57BL/6 mice vis-à-vis in Balb/c mice. Stabilization of PGE2 level by 15-hydroxyprostaglandin dehydrogenase inhibitor protected mice against anaphylaxis. Exogenous PGE2 attenuated bone marrow-derived cultured MC activation through EP2 and EP4 receptors. EP2 and EP4 agonism also curbed FcεRI-mediated degranulation of human MCs. Mechanistically, PGE2 interfered with the phosphorylation of phospholipase C gamma-1 and extracellular signal-regulated kinase. CONCLUSIONS: Homeostatic levels of PGE2 attenuate MC activation via EP2/EP4 and protect against anaphylaxis. Relative deficiency of PGE2 predisposes to anaphylaxis in humans and mice, whereas PGE2 stabilization protects against anaphylactic reactions.

Structural Insights into Novel 15-Prostaglandin Dehydrogenase Inhibitors.

We discovered SW033291 in a high throughput chemical screen aimed at identifying 15-prostaglandin dehydrogenase (15-PGDH) modulators. The compound exhibited inhibitory activity in in vitro biochemical and cell-based assays of 15-PGDH activity. We subsequently demonstrated that this compound, and several analogs thereof, are effective in in vivo mouse models of bone marrow transplant, colitis, and liver regeneration, where increased levels of PGE2 positively potentiate tissue regeneration. To better understand the binding of SW033291, we carried out docking studies for both the substrate, PGE2, and an inhibitor, SW033291, to 15-PGDH. Our models suggest similarities in the ways that PGE2 and SW033291 interact with key residues in the 15-PGDH-NAD+ complex. We carried out molecular dynamics simulations (MD) of SW033291 bound to this complex, in order to understand the dynamics of the binding interactions for this compound. The butyl side chain (including the sulfoxide) of SW033291 participates in crucial binding interactions that are similar to those observed for the C15-OH and the C16-C20 alkyl chain of PGE2. In addition, interactions with residues Ser138, Tyr151, and Gln148 play key roles in orienting and stabilizing SW033291 in the binding site and lead to enantioselectivity for the R-enantiomer. Finally, we compare the binding mode of (R)-S(O)-SW033291 with the binding interactions of published 15-PGDH inhibitors.

Dietary intake of walnut prevented Helicobacter pylori-associated gastric cancer through rejuvenation of chronic atrophic gastritis.

The fact that Fat-1 transgenic mice producing n-3 polyunsaturated fatty acids via overexpressed 3-desaturase significantly mitigated Helicobacter pylori (H. pylori)-associated gastric tumorigenesis through rejuvenation of chronic atrophic gastritis (CAG) led us to study whether dietary intake of walnut plentiful of n-3 PUFAs can be nutritional intervention to prevent H. pylori-associated gastric cancer. In our model that H. pylori-initiated, high salt diet-promoted gastric carcinogenesis, pellet diet containing 100 mg/kg and 200 mg/kg walnut was administered up to 36 weeks. As results, control mice (24 weeks) developed significant chronic CAG, in which dietary walnuts significantly ameliorated chronic atrophic gastritis. Expressions of COX-2/PGE2/NF-κB/c-Jun, elevated in 24 weeks control group, were all significantly decreased with walnut (p<0.01). Tumor suppressive enzyme, 15-PGDH, was significantly preserved with walnut. Control mice (36 weeks) all developed significant tumors accompanied with severe CAG. However, significantly decreased tumorigenesis was noted in group treated with walnuts, in which expressions of COX-2/PGE2/NF-κB/IL-6/STAT3, all elevated in 36 weeks control group, were significantly decreased with walnut. Defensive proteins including HO-1, Nrf2, and SOCS-1 were significantly increased in walnut group. Proliferative index as marked with Ki-67 and PCNA was significantly regulated with walnut relevant to 15-PGDH preservation. Conclusively, walnut can be an anticipating nutritional intervention against H. pylori.

Integrated eicosanoid lipidomics and gene expression reveal decreased prostaglandin catabolism and increased 5-lipoxygenase expression in aggressive subtypes of endometrial cancer.

Eicosanoids comprise a diverse group of bioactive lipids which orchestrate inflammation, immunity, and tissue homeostasis, and whose dysregulation has been implicated in carcinogenesis. Among the various eicosanoid metabolic pathways, studies of their role in endometrial cancer (EC) have very much been confined to the COX-2 pathway. This study aimed to determine changes in epithelial eicosanoid metabolic gene expression in endometrial carcinogenesis; to integrate these with eicosanoid profiles in matched clinical specimens; and, finally, to investigate the prognostic value of candidate eicosanoid metabolic enzymes. Eicosanoids and related mediators were profiled using liquid chromatography-tandem mass spectrometry in fresh frozen normal, hyperplastic, and cancerous (types I and II) endometrial specimens (n = 192). Sample-matched epithelia were isolated by laser capture microdissection and whole genome expression analysis was performed using microarrays. Integration of eicosanoid and gene expression data showed that the accepted paradigm of increased COX-2-mediated prostaglandin production does not apply in EC carcinogenesis. Instead, there was evidence for decreased PGE2 /PGF2α inactivation via 15-hydroxyprostaglandin dehydrogenase (HPGD) in type II ECs. Increased expression of 5-lipoxygenase (ALOX5) mRNA was also identified in type II ECs, together with proportional increases in its product, 5-hydroxyeicosatetraenoic acid (5-HETE). Decreased HPGD and elevated ALOX5 mRNA expression were associated with adverse outcome, which was confirmed by immunohistochemical tissue microarray analysis of an independent series of EC specimens (n = 419). While neither COX-1 nor COX-2 protein expression had prognostic value, low HPGD combined with high ALOX5 expression was associated with the worst overall and progression-free survival. These findings highlight HPGD and ALOX5 as potential therapeutic targets in aggressive EC subtypes. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

miR-21 modulates prostaglandin signaling and promotes gastric tumorigenesis by targeting 15-PGDH.

miR-21 is an abundantly expressed miRNA in mammalian cells, and evolutionarily conserved across a wide range of vertebrate species. The previous study found that miR-21 is significantly upregulated in gastric cancer. However, the detail mechanisms remain to be largely unknown. In current study, quantitative real-time PCR was applied to examine the expression of miR-21 in gastric cancer tissue and cell lines. The roles of miR-21 in cell proliferation and cell cycle were analyzed by cck8 cell viability assays, flow cytometry cell cycle assays and clone formation assays. As to detail mechanisms, we investigate the relationship between miR-21 and 15-PGDH in gastric cell lines, AGS and BGC-823 treated with In-miR-21, and found that miR-21 is negatively correlated with 15-PGDH. The reduced 15-PGDH may result in PGE2 accumulation which sustains carcinogenesis and tumor progression. We further found that miR-21 exert its oncogenic role through PGE2/PI3K/Akt/Wnt/ß-catenin axis in gastric cell proliferation. In conclusion, our findings enlarged our knowledge in the roles of miR-21 in the progression of gastric cancer.

Prostaglandin D2/J2 signaling pathway in a rat model of neuroinflammation displaying progressive parkinsonian-like pathology: potential novel therapeutic targets.

BACKGROUND: Prostaglandins are products of the cyclooxygenase pathway, which is implicated in Parkinson's disease (PD). Limited knowledge is available on mechanisms by which prostaglandins contribute to PD neurodegeneration. To address this gap, we focused on the prostaglandin PGD2/J2 signaling pathway, because PGD2 is the most abundant prostaglandin in the brain, and the one that increases the most under pathological conditions. Moreover, PGJ2 is spontaneously derived from PGD2. METHODS: In this study, we determined in rats the impact of unilateral nigral PGJ2-microinfusions on COX-2, lipocalin-type PGD2 synthase (L-PGDS), PGD2/J2 receptor 2 (DP2), and 15 hydroxyprostaglandin dehydrogenase (15-PGDH). Nigral dopaminergic (DA) and microglial distribution and expression levels of these key factors of the prostaglandin D2/J2 pathway were evaluated by immunohistochemistry. PGJ2-induced motor deficits were assessed with the cylinder test. We also determined whether oral treatment with ibuprofen improved the PD-like pathology induced by PGJ2. RESULTS: PGJ2 treatment induced progressive PD-like pathology in the rats. Concomitant with DA neuronal loss in the substantia nigra pars compacta (SNpc), PGJ2-treated rats exhibited microglia and astrocyte activation and motor deficits. In DA neurons, COX-2, L-PGDS, and 15-PGDH levels increased significantly in PGJ2-treated rats compared to controls, while DP2 receptor levels were unchanged. In microglia, DP2 receptors were basically non-detectable, while COX-2 and L-PGDS levels increased upon PGJ2-treatment, and 15-PGDH remained unchanged. 15-PGDH was also detected in oligodendrocytes. Notably, ibuprofen prevented most PGJ2-induced PD-like pathology. CONCLUSIONS: The PGJ2-induced rat model develops progressive PD pathology, which is a hard-to-mimic aspect of this disorder. Moreover, prevention of most PGJ2-induced PD-like pathology with ibuprofen suggests a positive feedback mechanism between PGJ2 and COX-2 that could lead to chronic neuroinflammation. Notably, this is the first study that analyzes the nigral dopaminergic and microglial distribution and levels of factors of the PGD2/J2 signaling pathway in rodents. Our findings support the notions that upregulation of COX-2 and L-PGDS may be important in the PGJ2 evoked PD-like pathology, and that neuronal DP2 receptor antagonists and L-PGDS inhibitors may be novel pharmacotherapeutics to relieve neuroinflammation-mediated neurodegeneration in PD, circumventing the adverse side effects of cyclooxygenase inhibitors.

High-mobility group box 1 suppresses resolvin D1-induced phagocytosis via induction of resolvin D1-inactivating enzyme, 15-hydroxyprostaglandin dehydrogenase.

High-mobility group box 1 (HMGB1) enhances inflammatory reactions by potentiating the activity of pro-inflammatory mediators and suppressing the phagocytosis of apoptotic neutrophils. However, the effects of HMGB1 on phagocytosis induced by pro-resolving mediators, such as resolvins, have not been studied up until this point. In this study, we investigated the effects and underlying mechanism of HMGB1 on resolvin D1-induced phagocytosis of MDA-MB-231 cells, which were selected as a model system based on their phagocytic capability and ease of transfecting them with a plasmid or siRNA in several cancer cell lines. Then we confirmed effects of HMGB1 in THP-1 cells. Resolvin D1 (RvD1) enhanced phagocytosis in MDA-MB-231 and THP-1 cells. HMGB1 suppressed RvD1-induced phagocytosis in MDA-MB.231 and THP-1 cells. HMGB1 dose-dependently induced the expression of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), the inactivating enzyme in pro-resolving lipid mediators such as RvE1 and RvD1. Involvement of 15-PGDH in-HMGB-1-induced suppression of phagocytosis was examined using siRNA of 15-PGDH or 15-PGDH inhibitor, TD23. Surprisingly, the silencing of 15-PGDH increased phagocytotic activity of MDA-MB-231 cells. TD23 also enhanced phagocytosis of MDA-MB-231 and THP-1 cells. In conclusion, the release of HMGB1 during the inflammatory phase induces 15-PGDH expression, which suppresses the phagocytotic activity of macrophages. These processes might be involved in the mechanism that blocks the resolution of inflammation, thereby allowing acute inflammation to progress to chronic inflammation.

Concerted actions of ameliorated colitis, aberrant crypt foci inhibition and 15-hydroxyprostaglandin dehydrogenase induction by sonic hedgehog inhibitor led to prevention of colitis-associated cancer.

The sonic hedgehog (Shh) signaling has been known to contribute to carcinogenesis in organ, where hedgehog exerted organogenesis and in cancers, which are developed based on mutagenic inflammation. Therefore, colitis-associated cancer (CAC) can be a good model to prove whether Shh inhibitors can be applied to prevent, as the efforts to discover potent anti-inflammatory agent are active to prevent CAC. Here, under the hypothesis that Shh inhibitors can prevent CAC, mouse model was generated to develop CAC by azoxymethane (AOM)-initiated, dextran sodium sulfate-promoted carcinogenesis. Shh inhibitors, cerulenin and itraconazole were treated by oral gavage and the mice were sacrificed at early phase of 3 weeks and late phase of 16 weeks. Compared to control group, the number of aberrant crypt foci at 3 weeks and tumor incidence at 16 weeks were all significantly decreased with Shh inhibitor. Significant attenuations of macrophage infiltration accompanied with significant decreases of IL-6, COX-2, STAT3 and NF-κB as well as significant ameliorations of ß-catenin nuclear translocation, cyclin D1 and CDK4 were imposed with Shh inhibitors. Especially, CAC was accompanied with significant cancellation of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), but their levels were significantly preserved with Shh inhibitors. Among inflammatory mediators, significantly decreased levels of IL-6 and TNF-α, regulated with repressed NF-κb and STAT3, were prominent with Shh inhibitor, whereas significant inductions of apoptosis were noted with Shh inhibitors. In conclusion, Shh inhibitors significantly prevented CAC covering either ameliorating oncogenic inflammation or suppressing tumor proliferation, especially supported with significant inhibition of IL-6 and STAT3 signaling, 15-PGDH preservation and apoptosis induction.

Endogenous conversion of ω-6 to ω-3 polyunsaturated fatty acids in fat-1 mice attenuated intestinal polyposis by either inhibiting COX-2/ß-catenin signaling or activating 15-PGDH/IL-18.

Omega-3 polyunsaturated fatty acids (ω-3PUFAs) have inhibitory effects in various preclinical cancer models, but their effects in intestinal polyposis have never been examined. As attempts have been made to use nutritional intervention to counteract colon cancer development, in this study we evaluated the effects of ω-3 PUFAs on intestinal polyposis in the Apc(Min/+) mouse model. The experimental groups included wild-type C56BL/6 mice, Apc(Min/+) mice, fat-1 transgenic mice expressing an n-3 desaturase to enable ω-3 PUFA synthesis, and Apc(Min/+) × fat-1 double-transgenic mice; all mice were 20 weeks of age. Small intestines were collected for gross and pathologic evaluation, including assessment of polyp number and size, followed by immunohistochemical staining and Western blotting. After administration of various concentrations of ω-3 PUFAs, PUFA levels were measured in small intestine tissue by GC/MS/MS analysis to compare with PUFA synthesis of between C57BL6 and fat-1mice. As a result, ω-3 PUFAs significantly attenuated Apc mutation-induced intestinal polyposis accompanied with significant inhibition of Wnt/ß-catenin signaling, COX-2 and PGE2, but induced significant levels of 15-PGDH. In addition, significant induction of the inflammasome-related substrates as IL-1ß and IL-18 and activation of caspase-1 was observed in Apc(Min/+) × fat-1 mice. Administration of at least 3 g/60 kg ω-3 PUFAs was equivalent to ω-3 PUFAs produced in fat-1 mice and resulted in significant increase in the expression of IL-1ß, caspase-3 and IL-18, as seen in Apc(Min/+) × fat-1 mice. We conclude that ω-3PUFAs can prevent intestinal polyp formation by inhibition of Wnt/ß-catenin signaling, but increased levels of 15-PGDH and IL-18.

Cell-based biological evaluations of 5-(3-bromo-4-phenethoxybenzylidene)thiazolidine-2,4-dione as promising wound healing agent.

Recent studies have focused on prostaglandin E2 (PGE2) because PGE2 regulates vertebrate hematopoietic stem cell induction and engraftment. PGE2 acts through EP2 and EP4 receptors to mediate regeneration and hematopoietic stem cell (HSC) development via the Wnt signaling pathway. Previously we reported that inhibitors of 15-PGDH can control the intracellular levels of PGE2. Therefore, we developed new potent 15-PGDH inhibitor, 5-(3-bromo-4-phenethoxybenzylidene)thiazolidine-2,4-dione (TD191), with an IC50 of 4 nM and tested cell-based wound healing effects. This compound significantly increased the level of PGE2 (451 pg/mL) in A549 cells, which was about 7-fold higher than that of control. HaCaT cells exposed to TD191 showed significantly improved wound healing after 48 h in scratch wound healing test, whereas treatment of TD191 to the fibroblast Hs27 cells slightly decreased cell growth compared with control. SCL is a basic helix-loop-helix transcription factor that is an essential for HSC development. By qPCR, SCL expression in HaCaT cells was 2-fold enhanced after addition of TD191, while treatment of TD191 into fibroblast Hs27 cells was not significantly changed the expression levels of the gene. This data provides in vitro evidence that TD191 may have utility for the therapeutic management of wound healing without scar formation.

Structure-activity relationship studies and biological characterization of human NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase inhibitors.

The structure-activity relationship (SAR) study of two chemotypes identified as inhibitors of the human NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase (HPGD, 15-PGDH) was conducted. Top compounds from both series displayed potent inhibition (IC50 <50 nM), demonstrate excellent selectivity towards HPGD and potently induce PGE2 production in A549 lung cancer and LNCaP prostate cancer cells.

In silico screening and in vivo experimental validation of 15-PGDH inhibitors from traditional Chinese medicine promoting liver regeneration.

The enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH), which acts as a negative regulator of prostaglandin E2 (PGE2) levels and activity, represents a promising pharmacological target for promoting liver regeneration. In this study, we collected data on 15-PGDH homologous family proteins, their inhibitors, and traditional Chinese medicine (TCM) compounds. Leveraging machine learning and molecular docking techniques, we constructed a prediction model for virtual screening of 15-PGDH inhibitors from TCM compound library and successfully screened genistein as a potential 15-PGDH inhibitor. Through further validation, it was discovered that genistein considerably enhances liver regeneration by inhibiting 15-PGDH, resulting in a significant increase in the PGE2 level. Genistein's effectiveness suggests its potential as a novel therapeutic agent for liver diseases, highlighting this study's contribution to expanding the clinical applications of TCM.

Inhibition of 15-hydroxyprostaglandin dehydrogenase protects neurons from ferroptosis in ischemic stroke.

Ischemic stroke is an acute serious cerebrovascular disease with high mortality and disability. Ferroptosis is an important regulated cell death (RCD) in ischemic stroke. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH), a degrading enzyme of prostaglandin E2 (PGE2), is shown to regulate RCD such as autophagy and apoptosis. The study aimed to determine whether 15-PGDH regulates ferroptosis and ischemic stroke, and further the exact mechanism. We demonstrated that overexpression of 15-PGDH in the brain tissues or primary cultured neurons significantly aggravated cerebral injury and neural ferroptosis in ischemic stroke. While inhibition of 15-PGDH significantly protected against cerebral injury and neural ferroptosis, which benefits arise from the activation of the PGE2/PGE2 receptor 4 (EP4) axis. While the impact of 15-PGDH was abolished with glutathione peroxidase 4 (GPX4) deficiency. Then, 15-PGDH inhibitor was found to promote the activation of cAMP-response element-binding protein (CREB) and nuclear factor kappa-B (NF-κB) via the PGE2/EP4 axis, subsequently transcriptionally upregulate the expression of GPX4. In summary, our study indicates that inhibition of 15-PGDH promotes the activation PGE2/EP4 axis, subsequently transcriptionally upregulates the expression of GPX4 via CREB and NF-κB, and then protects neurons from ferroptosis and alleviates the ischemic stroke. Therefore, 15-PGDH may be a potential therapeutic target for ischemic stroke.