Science Letters:EHPred: an SVM-based method for epoxide hydrolases recognition and classification

A two-layer method based on support vector machines (SVMs) has been developed to distinguish epoxide hydrolases (EHs) from other enzymes and to classify its subfamilies using its primary protein sequences. SVM classifiers were built using three different feature vectors extracted from the primary sequence of EHs: the amino acid composition (AAC), the dipeptide composition (DPC), and the pseudo-amino acid composition (PAAC). Validated by 5-fold cross tests, the first layer SVM clas- sifier can differentiate EHs and non-EHs with an accuracy of 94.2% and has a Matthew’s correlation coefficient (MCC) of 0.84. Using 2-fold cross validation, PAAC-based second layer SVM can further classify EH subfamilies with an overall accuracy of 90.7% and MCC of 0.87 as compared to AAC (80.0%) and DPC (84.9%). A program called EHPred has also been developed to assist readers to recognize EHs and to classify their subfamilies using primary protein sequences with greater accuracy.

Quantification of soluble epoxide hydrolase inhibitors in experimental and clinical samples using the nanobody-based ELISA

To ensure proper dosage of a drug,analytical quantification of it in biofluid is necessary.Liquid chromatography mass spectrometry(LC-MS)is the conventional method of choice as it permits accurate identification and quantification.However,it requires expensive instrumentation and is not appropriate for bedside use.Using soluble epoxide hydrolase(sEH)inhibitors(EC5026 and TPPU)as examples,we report development of a nanobody-based enzyme-linked immunosorbent assay(ELISA)for such small molecules and its use to accurately quantify the drug chemicals in human samples.Under optimized conditions,two nanobody-based ELISAs were successfully established for EC5026 and TPPU with low limits of detection of 0.085 ng/mL and 0.31 ng/mL,respectively,and two order of magnitude linear ranges with high precision and accuracy.The assay was designed to detect parent and two biologically active metabolites in the investigation of a new drug candidate EC5026.In addition,the ELISAs displayed excellent correlation with LC-MS analysis and evaluation of inhibitory potency.The results indicate that nanobody-based ELISA methods can efficiently analyze drug like compounds.These methods could be easily implemented by the bedside,in the field in remote areas or in veterinary practice.This work illustrates that nanobody based assays offer alternative and supplementary analytical tools to mass spectrometry for monitoring small molecule medicines during clinical development and therapy.Attributes of nanobody based pharmaceutical assays are discussed.

Influence of Silencing Soluble Epoxide Hydrolase with RNA Interference on Cardiomyocytes Apoptosis Induced By Doxorubicin

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 1 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（P0.01）.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（P0.01）.However,the expression levels of Bax were decreased,those of Bcl-2 increased and the apoptosis rate of cardiomyocytes obvi-ously decreased in EH-R＋DOX group when compared with those in the DOX group and the PCN＋DOX group（P0.01 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.

Using multiple site-directed modification of epoxide hydrolase to significantly improve its enantioselectivity in hydrolysis of rac-glycidyl phenyl ether

The epoxide hydrolase gene(SpEH) from Sphingomonas sp. HXN-200 was synthesized and expressed in robust Escherichia coli cells that had a dual protection system. The enantioselectivity(E-value) of the recombinant SpEH was 7.7 and the yield of the remaining(R)-PGE was 24.3% for the hydrolysis of racemic phenyl glycidyl ether(rac-PGE). To improve the catalytic properties of SpEH, the site-directed mutagenesis was carried out based on homology modeling, sequence alignment and molecular docking. Six residues(V195, V196, F218,N226, Q312, and M332) near the active site were mutated to hydrophobic amino acids and the positive mutations were selected for combinatorial mutation. The optimal mutant SpEH^(V196A/N226A/M332A) had an enhanced E-value of 21.2 and a specific activity of 4.57 U·mg^-1-wet cells, which were 2.8-, and 2.3-fold higher than those of wild-type SpEH. The optimal temperature and p H for purified Sp EHV196 A/N226 A/M332 Ato catalyze the hydrolysis of rac-PGE were 25 ℃ and 7.0 with 200 U·mg^-1. The enantioselectivity and yield of the remaining(R)-PGE of E. coliSpEH^(V196A/N226A/M332A)increased from 7.7 to 21.2 and 24.3% to 40.9%, respectively. The molecular docking and kinetic parameter analyses showed that SpEH^(V196A/N226A/M332A) has a greater affinity toward(S)-PGE than(R)-PGE, and that it was more difficult for the O-atom of ASP170 to achieve the nucleophilic attack on the Cα of(R)-PGE, resulting in its improved enantioselectivity.

CYP1A1,CYP2E1 and EPHX1 polymorphisms in sporadic colorectal neoplasms

AIM To investigate the contribution of polymorphisms in the CYP1A1, CYP2E1 and EPHX1 genes on sporadic colorectal cancer(SCRC) risk. METHODS Six hundred forty-one individuals(227 patients with SCRC and 400 controls) were enrolled in the study. The variables analyzed were age, gender, tobacco and alcohol consumption, and clinical and histopathological tumor parameters. The CYP1A1 *2A, CYP1A1 *2C CYP2E1 *5B and CYP2E1 *6 polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). The EPHX1 Tyr113 His, EPHX1 His139 Arg and CYP1A1 *2C polymorphisms were detected by real-time PCR. Chisquared test and binary logistic regression were used in the statistical analysis. Haplotype analysis was conducted using the Haploview program, version 2.05.RESULTS Age over 6 2 years was a risk factor for SCRC development(OR = 7.54, 95%CI: 4.94-11.50, P < 0.01). Male individuals were less susceptible to SCRC(OR = 0.55, 95%CI: 0.35-0.85, P < 0.01). The CYP2E1*5B polymorphism was associated with SCRC in the codominant(heterozygous genotype: OR = 2.66, 95%CI: 1.64-4.32, P < 0.01), dominant(OR = 2.82, 95%CI: 1.74-4.55, P < 0.01), overdominant(OR = 2.58, 95%CI: 1.59-4.19, P < 0.01), and log-additive models(OR = 2.84, 95%CI: 1.78-4.52, P < 0.01). The CYP2E1*6 polymorphism was associated with an increased SCRC risk in codominant(heterozygous genotype: OR = 2.81, 95%CI: 1.84-4.28, P < 0.01; homozygous polymorphic : OR = 7. 3 2, 9 5 % C I : 1.85-28.96, P < 0.01), dominant(OR = 2.97, 95%CI: 1.97-4.50, P < 0.01), recessive(OR = 5.26, 95%CI: 1.35-20.50, P = 0.016), overdominant(OR = 2.64, 95%CI: 1.74-4.01, P < 0.01), and log-additive models(OR = 2.78, 95%CI: 1.91-4.06, P < 0.01). The haplotype formed by the minor alleles of the CYP2E1*5B(C) and CYP2E1*6(A) polymorphisms was associated with SCRC(P = 0.002). However, the CYP1A1 *2A, CYP1A1 *2C, EPHX1 Tyr113 His and EPHX1 His139 Arg polymorphisms were not associated with SCRC.CONCLUSION In conclusion, the results demonstrated that CYP2E1*5B and CYP2E1*6 minor alleles play a role in the development of SCRC.

Increased Soluble Epoxide Hydrolase Activity Positively Correlates with Mortality in Heart Failure Patients with Preserved Ejection Fraction:Evidence from Metabolomics

Epoxyeicosatrienoic acids(EETs)have pleiotropic endogenous cardiovascular protective effects and can be hydrolyzed to the corresponding dihydroxyeicosatrienoic acids by soluble epoxide hydrolase(sEH).Heart failure with preserved ejection fraction(HFpEF)has shown an increased prevalence and worse prognosis over the decades.However,the role of sEH activ-ity in HFpEF remains unclear.We enrolled 500 patients with HFpEF and 500 healthy controls between February 2010 and March 2016.Eight types of sEH-related eicosanoids were measured according to target metabolomics,and their correlation with clinical endpoints was also analyzed.The primary endpoint was cardiac mortality,and the secondary endpoint was a composite of cardiac events,including heart failure(HF)readmission,cardiogenic hospitalization,and all-cause mortal-ity.Furthermore,the effect of sEH inhibitors on cardiac diastolic function in HFpEF was investigated in vivo and in vitro.Patients with HFpEF showed significantly enhanced EET degradation by the sEH enzyme compared with healthy controls.More importantly,sEH activity was positively correlated with cardiac mortality in patients with HFpEF,especially in older patients with arrhythmia.A consistent result was obtained in the multiple adjusted models.Decreased sEH activity by the sEH inhibitor showed a significant effective effect on the improvement of cardiac diastolic function by ameliorating lipid disorders in cardiomyocytes of HFpEF mouse model.This study demonstrated that increased sEH activity was associated with cardiac mortality in patients with HFpEF and suggested that sEH inhibition could be a promising therapeutic strategy to improve diastolic cardiac function.Clinical trial identifier:NCT03461107(https://clini caltr ials.gov).

Relationship between polymorphisms of genes encoding microsomal epoxide hydrolase and glutathione S-transferase P1 and chronic obstructive pulmonary disease

Background Cigarette smoking is the major risk factor for chronic obstructive pulmonary disease (COPD) However, only 10%-20% of chronic heavy cigarette smokers develop symptomatic disease COPD is most likely the result of complex interactions between environmental and genetic factors Genetic susceptibility to COPD might depend on the variations in enzyme activities that detoxify cigarette smoke products, such as microsomal epoxide hydrolase (mEH) and glutathione S-transferase (GST) In this study, we investigated the relationship between polymorphisms in the genes encoding mEH and glutathione S-transferase P1 (GSTP1) and COPD in a Chinese population Methods Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to find mEH polymorphism in exon 3 (Tyr113→His), exon 4 (His139→Arg) and GSTP1 polymorphism in exon 5 (Ile105→Val) in 100 COPD patients and 100 age- and sex-matched healthy controls Results The proportion of mEH exon 3 heterozygotes was significantly higher in patients with COPD than that in the control subjects (42% vs 32%) The odds ratio ( OR ) adjusted by age, sex, body mass index (BMI) and cigarette years was 2 96 (95% CI 1 24-7 09) There was no marked difference in very slow activity genotype versus other genotypes between COPD patients and the controls When COPD patients were non-smokers, the OR of very slow activity genotype versus other genotypes was more than 1 00; and when COPD patients were smokers (current smokers and ex-smokers), the OR was less than 1 00 There was no significant difference in GSTP1 polymorphism adjusted by age, sex, BMI and smoking between COPD patients and the controls Conclusions mEH exon 3 heterozygotes might be associated with susceptibility to COPD in China The interaction might exist between mEH genotype and smoke The gene polymorphism for GSTP1 might not be associated with susceptibility to COPD in the Chinese population

The Association Between Epoxide Hydrolase Genetic Variant and Effectiveness of Nicotine Replacement Therapy in a Han Chinese Population

Dear Editor, Nicotine is a psychoactive alkaloid that is thought to play a key role in addiction to commercial tobacco products [1] and cotinine is its primary metabolite [2]. Pharmacological treatment, such as nicotine replacement therapy （NRT）, is a valid solution to this problem. Tobacco smoke contains many carcinogens such as nitrosamines .

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.

Association of the genetic polymorphism of EPHX1 and EPHX2 with the susceptibility to chronic benzene poisoning

The aim of this study was to explore the association of the genetic polymorphism of EPHX1 and EPHX2 with the susceptibility to chronic benzene poisoning(CBP).A case-control study of 268 patients with CBP and 268 healthy workers matched by age and sex,all of whom were occupationally exposed to benzene,was conducted.The single nucleotide polymorphisms(SNPs,rs2854451,rs3738047,rs2234922 and rs1051741)of EPHX1 gene and the SNP(rs751141)of EPHX2 gene were tested by the TaqMan PCR method.In the subjects carrying the genotype of EPHX1 rs3738047 GG,the risk of CBP was decreased in the individuals simultaneously carrying EPHX1 rs2234922 G(P=0.02).Alternatively,in the subjects carrying the genotype of EPHX1 rs2234922 AA,the risk of CBP was increased in the individuals simultaneously carrying the allele of EPHX2 rs751141A(P=0.03).It was also found that there were potential interactions between alcohol consumption and the polymorphism of EPHX1 rs1051741(x_(H)^(2)=5.28,P=0.02)or rs2234922(x_(H)^(2)=6.71,P=0.01).Compared to individuals with EPHX1 rs1051741 CC or rs2234922 AA genotype in the drinkers,the risk of CBP in those carrying genotypes of EPHX1 rs1051741 CT+TT or rs2234922 AG+GG was decreased,respectively(P=0.04,P<0.01).Haplotype analysis of polymorphisms in EPHX1 showed that the risk of CBP was increased in the subjects with haplotype 2(rs2854451-A,rs3738047-G,rs2234922-A,rs1051741-C)or haplotype 4(rs2854451-G,rs3738047-A,rs2234922-G,rs1051741-T),but decreased in those with haplotype 6(rs2854451-G,rs3738047-G,rs2234922-G,rs1051741-T)or haplotype 10(rs2854451-A,rs3738047-A,rs2234922-G,rs1051741-T),respectively.Logistic regression analysis revealed that smoking might play a role in modifying the risk of CBP(OR=0.313,95%CI:0.123–0.794,P=0.015).The genetic polymorphism in EPHX1 may be associated with the risk of CBP in the Chinese occupational population and further research is needed for the association between the genetic polymorphism in EPHX2 and the susceptibility to CBP.

Clinical significance of EPHX2 deregulation in prostate cancer

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.