Structure-guided discovery of potent and oral soluble epoxide hydrolase inhibitors for the treatment of neuropathic pain

Soluble epoxide hydrolase (sEH) is related to arachidonic acid cascade and is over-expressed in a variety of diseases, making sEH an attractive target for the treatment of pain as well as inflammatory-related diseases. A new series of memantyl urea derivatives as potent sEH inhibitors was obtained using our previous reported compound 4 as lead compound. A preferential modification of piperidinyl to 3-carbamoyl piperidinyl was identified for this series via structure-based rational drug design. Compound A20 exhibited moderate percentage plasma protein binding (88.6%) and better metabolic stability in vitro. After oral administration, the bioavailability of A20 was 28.6%. Acute toxicity test showed that A20 was well tolerated and there was no adverse event encountered at dose of 6.0 g/kg. Inhibitor A20 also displayed robust analgesic effect in vivo and dose-dependently attenuated neuropathic pain in rat model induced by spared nerve injury, which was better than gabapentin and sEH inhibitor (±)-EC-5026. In one word, the oral administration of A20 significantly alleviated pain and improved the health status of the rats, demonstrating that A20 was a promising candidate to be further evaluated for the treatment of neuropathic pain.

Clinical significance of EPHX2 deregulation in prostate cancer / 亚洲男科学杂志(英文版)

The arachidonic acid (AA) metabolic pathway participates in various physiological processes as well as in the development of malignancies. We analyzed genomic alterations in AA metabolic enzymes in the Cancer Genome Atlas (TCGA) prostate cancer (PCa) dataset and found that the gene encoding soluble epoxide hydrolase (EPHX2) is frequently deleted in PCa. EPHX2 mRNA and protein expression in PCa was examined in multiple datasets by differential gene expression analysis and in a tissue microarray by immunohistochemistry. The expression data were analyzed in conjunction with clinicopathological variables. Both the mRNA and protein expression levels of EPHX2 were significantly decreased in tumors compared with normal prostate tissues and were inversely correlated with the Gleason grade and disease-free survival time. Furthermore, EPHX2 mRNA expression was significantly decreased in metastatic and recurrent PCa compared with localized and primary PCa, respectively. In addition, EPHX2 protein expression correlated negatively with Ki67 expression. In conclusion, EPHX2 deregulation is significantly correlated with the clinical characteristics of PCa progression and may serve as a prognostic marker for PCa.

Analgesic effects of soluble epoxide hydrolase inhibitor in K/BxN serum transfer arthritis mouse model

BACKGROUND: Soluble epoxide hydrolase (sEH) is an enzyme that converts epoxyeicosatrienoic acid (EET) into the anti-inflammatory dihydroxyeicosatrienoic acids (DHET). Inhibition of sEH by the potent soluble epoxide hydrolase inhibitor (sEHI) decreases inflammation by increasing EET. The K/BxN serum transfer mouse model of arthritis displays an initial inflammation and an associated tactile allodynia that continues on following the resolution of inflammation. METHODS: We undertook the following studies: i) Using the K/BxN mouse model, we examined effects on allodynia during the early inflammatory phase of administration of sEHI 3 mg/kg and/or diclofenac (DFC) 10 mg/kg. ii) In the late inflammatory phase, we administered sEHI (3, 10, or 30 mg/kg); DFC 10 mg/kg; gabapentin 100 mg/kg. iii) Using the conditioned place preference (CPP) we examined the synergism between sEHI and DFC in the K/BxN mouse using the CPP paradigm. The drug was administered intraperitoneally and the allodynia was measured with the von Frey test. RESULTS: In the early phase, both sEHI and DFC displayed an antiallodynic action. In the late phase, sEHI, and gabapentin but not DFC were effective in reversing the allodynia. Comparable results were observed with the CPP. CONCLUSIONS: This study demonstrates that sEHI reduces mechanical allodynia in both the early and the late inflammatory K/BxN mouse model of arthritis. The sEHI target thus addresses the hyperalgesia arising from inflammation as well as the post-inflammatory phase that has been said to reflect neuropathic-like states, thus presenting alternatives to the limited efficacy of arthritis drugs in use.

Active maintenance of endothelial cells prevents kidney fibrosis

BACKGROUND: Soluble epoxide hydrolase (sEH) expressed by endothelial cells catalyzes the metabolism of epoxyeicosatrienoic acids (EETs), which are vasoactive agents. METHODS: We used a unilateral ureteral obstruction mouse model of kidney fibrosis to determine whether inhibition of sEH activity reduces fibrosis, the final common pathway for chronic kidney disease. RESULTS: sEH activity was inhibited by continuous release of the inhibitor 12-(3-adamantan-1-ylureido)-dodecanoic acid (AUDA) for 1 or 2 weeks. Treatment with AUDA significantly ameliorated tubulointerstitial fibrosis by reducing fibroblast mobilization and enhancing endothelial cell activity. In an in vitro model of endothelial-to-mesenchymal transition (EndMT) using human vascular endothelial cells (HUVECs), AUDA prevented the morphologic changes associated with EndMT and reduced expression of fibroblast-specific protein 1. Furthermore, HUVECs activated by AUDA prevented the epithelial-to-mesenchymal transition (EMT) of tubular epithelial cells in a co-culture system. CONCLUSION: Our findings suggest that regulation of sEH is a potential target for therapies aimed at delaying the progression of kidney fibrosis by inhibiting EndMT and EMT.

Active maintenance of endothelial cells prevents kidney fibrosis

BACKGROUND: Soluble epoxide hydrolase (sEH) expressed by endothelial cells catalyzes the metabolism of epoxyeicosatrienoic acids (EETs), which are vasoactive agents. METHODS: We used a unilateral ureteral obstruction mouse model of kidney fibrosis to determine whether inhibition of sEH activity reduces fibrosis, the final common pathway for chronic kidney disease. RESULTS: sEH activity was inhibited by continuous release of the inhibitor 12-(3-adamantan-1-ylureido)-dodecanoic acid (AUDA) for 1 or 2 weeks. Treatment with AUDA significantly ameliorated tubulointerstitial fibrosis by reducing fibroblast mobilization and enhancing endothelial cell activity. In an in vitro model of endothelial-to-mesenchymal transition (EndMT) using human vascular endothelial cells (HUVECs), AUDA prevented the morphologic changes associated with EndMT and reduced expression of fibroblast-specific protein 1. Furthermore, HUVECs activated by AUDA prevented the epithelial-to-mesenchymal transition (EMT) of tubular epithelial cells in a co-culture system. CONCLUSION: Our findings suggest that regulation of sEH is a potential target for therapies aimed at delaying the progression of kidney fibrosis by inhibiting EndMT and EMT.

Effect and mechanism of soluble epoxide hydrolase inhibitor in renal fibrosis mice model / 中华肾脏病杂志

Objective To investigate the effect and mechanism of soluble epoxide hydrolase inhibitor (sEHI) for NF-κB pathway and cell circle arrest of tubular epithelial cell in unilateral ureteral obstruction (UUO) mice model.Methods Thirty-two healthy C57BL/6 male mice performed UUO surgery to induce renal interstitial fibrosis.Animals were randomly divided into 4 groups:sham group (n=8),sEHI (1 mg· kg-1·d-1) group (n=8),UUO group (n=8) and UUO+sEHI (1 mg· kg-1· d-1) group (n=8).Daily sEHI [1-(1-methylsulfonyl-piperidin-4-yl)-3-(4-trifluoromethoxy-phenyl)-urea,TUPS] or 2％ DMSO was applied to mice by oral gavage from day 1 to day 14 after surgery.All mice were sacrificed at day 14 and kidneys were harvested for further analysis.The changes of renal tissue morphology and pathology were observed by Hematoxylin and eosin (HE) and sirius red staining.The expressions of sEH,nuclear factor κB p65 (NF-κB p65) and IκB were measured by Western blotting.The expressions of TNF-α,IL-1β,MCP-1,IL-6,TGF-β,CTGF,collagen-Ⅳ and α-SMA were analyzed by real-time PCR.Immunofluorescence staining of phospho-histone H3 (p-HH3) and Ki67 was performed to determine the stage of cell cycle G2/M arrest.Results The expression and activity of sEH increased in UUO group (P ＜ 0.05).Administration of sEHI inhibited activity of sEH and infiltration of inflammatory cell in tubular interstitial,as well as attenuated tubular damage and tubular interstitial fibrosis.Western blotting analysis revealed administration of sEHI inhibited up-regulated NF-κB p65 and down-regulated IκB in UUO group (P ＜ 0.05).Real-time PCR demonstrated that administration of sEHI obviously decreased the mRNA expression of cytokines and fibrosis markers,including of TNF-α,IL-1 β,MCP-1,IL-6,TGF-β,CTGF,Collagen-Ⅳ,α-SMA (P ＜ 0.05).Immunofluorescence staining showed that there were much more p-HH3 and Ki67 double positive nuclear tubular epithelial cells and interstitial cells in UUO group,compared with Sham group (P ＜ 0.05).Administration of sEHI reduced the number of double positive nuclear cell only in tubular epithelial cells (P ＜ 0.05),but not in interstitial cells.Conclusions In UUO tubular interstitial fibrosis model,sEHI inhibits the activation of NF-κB pathway by down-regulating p65 and up-regulating IκB and ameliorates the infiltration of inflammatory cells.In addition,sEHI plays anti-fibrosis effect by moderating cell cycle G2/M arrest and reducing the excrete of pro-fibrosis factors of tubular epithelial cells.

Pharmacological research progress of myocardial ischemia based on the metabonomics / 中国药学杂志

Cardiac hypo-function caused by myocardial ischemia is considered as the first killer of human health. The related metabolites in body can be changed due to the lack of blood and oxygen. These metabolites generated by pathological and physiology changes or exogenous intervention are extreme complicated, and the existing test methods can't satisfy the prospected purpose due to the lower sensitivity, more narrow liner range and so on. Therefore, the concept of metabonomics, a systemic analysis method, was put forward. Metabolites can be quantified in temporal and spatial dimension by metabonomics featured in a high throughput, higher detective sensitivity and wider liner range manner. So it has gradually been applied to many areas including myocardial ischemia. In this paper, based on the comprehensive research literature in domestic and overseas in recent years, the application of metabonomics in pharmacological research of myocardial ischemia was summarized. Five kinds of metabolic pathways are related with myocardial ischemia including sugar metabolism, energy metabolism, amino acid metabolism, purine metabolism and soluble epoxide hydrolase table oxidase P450 metabolism. Some drugs can be used to myocardial ischemia via these pathways. These representative drugs and their mechanisms which are analyzed by metabonomics were concluded in this paper.

Soluble Epoxide Hydrolase Inhibitory Activity from Euphorbia supina Rafin

In our search for natural soluble epoxide hydrolase (sEH) inhibitors from plants, an extract of the dried whole plants of Euphorbia supina Rafin was found to significantly inhibit sEH activity in vitro. Phytochemical investigation of E. supina resulted in isolation of 17 compounds (1 - 17), including triterpenes (1 - 4), phenolic compounds (5 - 8), and flavonoid derivatives (9 - 17). The structures of the isolated compounds were established mainly by extensive analysis of the 1D and 2D NMR, and MS data. All of the isolated compounds were evaluated for their sEH inhibitory activity. Among the isolated phenolic compounds, 8 was identified as a significant inhibitor of sEH, with an IC50 value of 15.4 +/- 1.3 microM. Additionally, a kinetic analysis of isolated compounds (2, 5, 8 - 11, 13, and 17) indicated that the inhibitory effects of flavonoid derivatives 10 and 11 were of mixed-type, with inhibitory constants (Ki) ranging from 3.6 +/- 0.8 to 21.8 +/- 1.0 microM, whereas compounds 2, 5, 8, 9, 13, and 17 were non-competitive inhibitors with inhibition Ki values ranging from 3.3 +/- 0.2 to 39.5 +/- 0.0 microM.

Epi-Leptosphaerin: A New L-Isoascorbic Acid Derivative from Marine Sponges

A new L-isoascorbic acid derivative epi-leptosphaerin (1) and two known compounds leptosphaerin (2), and verongamine (3) were isolated from sponges of the orders Verongida and Thorectidae. Compounds 1 and 2 are most likely of sponge-associated fungal origin. In the present study, isolated compounds were investigated for their inhibition of soluble epoxide hydrolase (sEH), which is considered a promising target for the management of pain, inflammation, and comorbidities associated with diabetes. Compound 3, verongamine, displayed weak inhibitory activity against sEH with an IC50 value 51.5 +/- 1.0 microM.

Phytochemical Constituents from the Aerial Part of Ducrosia ismaelis Asch

Phytochemical investigation of the aerial components of Ducrosia ismaelis Asch. led to the isolation of six known compounds, psoralen (1), isopsoralen (2), cnidioside A (3), (-)-syringaresinol-O-beta-D-glucopyranoside (4), (E)-plicatin B (5), trilinolein (6). The chemical structures of these compounds were elucidated from spectroscopic data and by comparison of these data with previously published results. The antioxidant, anti-osteoporotic and cardiovascular related activities of the isolated compounds were assessed using oxygen radical absorbance capacity (ORAC), reducing capacity, tartrate-resistant acid phosphatase (TRAP), and soluble epoxide hydrolase (sEH) inhibitory activity assays. Compounds (3-5) showed potent peroxyl radical-scavenging capacities with ORAC values of 11.06 +/- 0.39, 7.98 +/- 0.10, and 13.99 +/- 0.06 Trolox equivalent (TE) at concentrations of 10 microM, respectively. Only compounds 4 and 5 was able to significantly reduce Cu2+ ions, with a reduction value of 9.06 +/- 0.32 and 4.61 +/- 0.00 microM Trolox Equivalent (TE) at a concentration of 10 microM. Compound 5 at 10 microM exhibited a potent inhibitory effect on osteoclastic TRAP activity with a TRAP value of 86.05 +/- 6.55% of the control. Compounds 1, 3 and 5 potently inhibited sEH activity with IC50 values of 41.6 4.9, 16.0 1.1, and 49.0 5.7 microM, respectively.

Isolation and Structure Determination of an Imidazo-pyrimidine, 5-Chlorocavernicolin, Maleimide oximes and Nucleosides from a Marine Sponge Extract

In a continuation of our studies to discover bioactive secondary metabolites from marine sources, we further investigated samples from a tryptamine and phenyl-alkane producing sponge, which resulted in the isolation of four uncommon small molecules and five nucleosides. Their structures were determined to be 7,8-dihydroimidazo[1,5-c]pyrimidin-5(6H)-one (1), 5-chlorocavernicolin (2), maleimide-5-oxime (3), 3-methylmaleimide-5-oxime (4), uridine (5), 2'-deoxyuridine (6), thymidine (7), adenine (8), and adenosine (9) by spectroscopic analyses. The isolated compounds were evaluated for inhibitory activity against soluble epoxide hydrolase (sEH) as well as the Wnt/beta-catenine signaling pathway.

The effects of soluble epoxide hydrolase inhibitors on cholesterol efflux in adipocytes / 中华内科杂志

Objective To observe the effects of soluble epoxide hydrolase inhibitors tAUCB on cholesterol efflux in adipocytes. Methods 3T3-L1 preadipocytes were induced to differentiation and maturation. Cells were stimilated with 100μg/L LPS after starved for 24 hours, then tAUCB in various concentrations(1 ,10,50,100 μmol/L)were added for 24 h, or incubated with the peroxisome proliferator activated receptor gamma (PPARy) antagonist GW9662 (5 μmol/L).0μmol/L tAUCB treated group was taken as empty control. After then, the mRNA expression of PPARγ and adenosine triphosphate binding cassette transporter Al (ABCA1) in cells were determined via realtime-PCR, the amounts of protein expression of PPARγand ABCA1 in cells were detected by Western blot, the efflux rates of 3H-cholesterol in cells were detected by means of liquid scintillation counter. Results tAUCB could dose-dependently increase the apolipoprotein A1 (apoA1)-mediated cholesterol efflux in adipocytes. After stimulated by 1, 10,50,100 μmol/L tAUCB, cholesterol efflux rates were (5.93±0.66) %, (7.40 ± 0. 43) %, (8. 30 ±0. 34)% ,(9.77±0.42)% respectively, there were significant difference after treated by 10-100 μmol/L tAUCB compared with control(5.67±0.17)%(P＜0.05). With the concentration of tAUCB increased,ABCA1, PPAR mRNA and protein expression were also dose-dependently up-regulated. GW9662 could significantly inhibit the effects of tAUCB, and then reduce the cholesterol efflux and the expression of PPARγ and ABCA1 in adipocytes. Conclusions tAUCB could up-regulate PPARγ expression in adipocytes, and promote the cholesterol efflux of adipocytes via apoA1-ABCA1 pathway, which might decrease the cellular cholesterol accumulation in adipocytes.

Influence of Silencing Soluble Epoxide Hydrolase with RNA Interference on Cardiomyocytes Apoptosis Induced By Doxorubicin / 华中科技大学学报（医学）（英德文版）

In order to investigate the influence of silencing soluble epoxide hydrolase (sEH) with double-stranded small interfering RNA (siRNA) on cardiomyocytes apoptosis induced by doxorubicin (DOX),two plasmids containing siRNA sequences specific to sEH were constructed and transfected into the primary cultured cardiomyocytes by using FuGENE HD transfection agents.The mRNA and protein expression levels of sEH were detected by semiquantitative RT-PCR and Western blotting respectively,and the plasmids that silenced sEH most significantly were selected,and renamed EH-R.The plasmids carrying a nonspecific siRNA coding sequence (PCN) served as the negative control.Cardiomyocytes were divided into four groups:control group,DOX group,PCN+DOX group,and EH-R+DOX group.Apoptosis of cardiomyocytes was induced by DOX at a concentration of l μmol/L.Apoptosis rate of cardiomyocytes was determined by flow cytometery.The protein expression levels of Bcl-2 and Bax were detected by Western blotting.The results showed that the expression of sEH was down-regulated by EH-R plasmid.The expression levels of sEH mRNA and protein in the EH-R+DOX group were significantly decreased as compared with other groups (P＜0.01).As compared with the control group,the apoptosis rate of cardiomyocytes in three DOX-treated groups was obviously increased,the expression levels of Bax increased,and those of Bcl-2 decreased (P＜0.01).However,the expression levels of Bax were decreased,those of Bcl-2 increased and the apoptosis rate of cardiomyocytes obviously decreased in EH-R+DOX group when compared with those in the DOX group and the PCN+DOX group (P＜0.01 for each).It was concluded that the recombinant plasmids could be successfully constructed,and transfected into the primary cultured cardiomyocytes.They could ameliorate the DOX-induced cardiomyocytes apoptosis by selectively inhibiting the expression of sEH with RNAi and increasing the expression of Bcl-2.