Epoxyeicosatrienoic Acids Prevent Cardiac Dysfunction in Viral Myocarditis via Interferon Type I Signaling

Myocarditis is a challenging inflammatory disease of the heart, and better understanding of its pathogenesis is needed to develop specific drug therapies. Epoxyeicosatrienoic acids (EETs), active molecules synthesized by CYP (cytochrome P450) enzymes from arachidonic acids and hydrolyzed to less active dihydroxyeicosatrienoic acids by sEH (soluble epoxide hydrolase), have been attributed anti-inflammatory activity. Here, we investigated whether EETs have immunomodulatory activity and exert protective effects on coxsackie B3 virus-induced myocarditis. Viral infection altered eicosanoid epoxide and diol levels in both patients with myocarditis and in the murine heart and correlated with the increased expression and activity of sEH after coxsackie B3 virus infection. Administration of a sEH inhibitor prevented coxsackie B3 virus-induced cardiac dysfunction and inflammatory infiltration. Importantly, EET/sEH inhibitor treatment attenuated viral infection or improved viral resistance by activating type I IFN (interferon) signaling. At the molecular level, EETs enhanced the interaction between GSK3β (glycogen synthase kinase-3 beta) and TBK1 (TANK-binding kinase 1) to promote IFN-β production. Our findings revealed that EETs and sEH inhibitors prevent the progress of coxsackie B3 virus-induced myocarditis, particularly by promoting viral resistance by increasing IFN production.

Proteasome Inhibitors and Their Pharmacokinetics, Pharmacodynamics, and Metabolism

The proteasome is responsible for mediating intracellular protein degradation and regulating cellular function with impact on tumor and immune effector cell biology. The proteasome is found predominantly in two forms, the constitutive proteasome and the immunoproteasome. It has been validated as a therapeutic drug target through regulatory approval with 2 distinct chemical classes of small molecular inhibitors (boronic acid derivatives and peptide epoxyketones), including 3 compounds, bortezomib (VELCADE), carfilzomib (KYPROLIS), and ixazomib (NINLARO), for use in the treatment of the plasma cell neoplasm, multiple myeloma. Additionally, a selective inhibitor of immunoproteasome (KZR-616) is being developed for the treatment of autoimmune diseases. Here, we compare and contrast the pharmacokinetics (PK), pharmacodynamics (PD), and metabolism of these 2 classes of compounds in preclinical models and clinical studies. The distinct metabolism of peptide epoxyketones, which is primarily mediated by microsomal epoxide hydrolase, is highlighted and postulated as a favorable property for the development of this class of compound in chronic conditions.

GSK2256294 Decreases sEH (Soluble Epoxide Hydrolase) Activity in Plasma, Muscle, and Adipose and Reduces F2-Isoprostanes but Does Not Alter Insulin Sensitivity in Humans

[Figure: see text].

Oxidative stress-related genes (EPHX1 and MnSOD) polymorphism and risk of pre-eclampsia: a meta-analysis

BACKGROUND

Previous studies have detected the association of polymorphisms in oxidative stress-related genes EPHX1 and MnSOD with pre-eclampsia (PE) risk, but the results are inconsistent among studies. Thus, a meta-analysis was performed to obtain more conclusive results.

METHODS

Eligible studies were retrieved in PubMed, Web of Science, EMBASE, Scopus, and CNKI. Odds ratios (ORs) with 95% confidence intervals (CIs) were utilized to evaluate the relationship between EPHX1 rs1051740, EPHX1 rs2234922, MnSOD rs4880 polymorphisms, and PE susceptibility in the genetic models. The subgroup analysis was also performed.

RESULTS

Fourteen studies with a total of 4250 participants were included, including 1784 PE patients and 2466 healthy women. There was a statistically significant association between EPHX1 rs1051740 polymorphism and PE in Caucasians within the allele, dominant, heterozygous, and homozygous models (OR = 0.79, 95% CI = 0.64-0.98; OR = 0.64, 95% CI = 0.47-0.87; OR = 0.61, 95% CI = 0.44-0.85; OR = 0.63, 95% CI = 0.42-0.97, respectively). There was a statistically significant association between EPHX1 rs2234922 polymorphism and PE in Middle Easterners within the recessive and homozygous models (OR = 3.59, 95% CI = 1.25-10.32; OR = 3.99, 95% CI = 1.38-11.49, respectively). There was no statistically significant association between MnSOD rs4880 polymorphism and PE within five genetic models. Subgroup analysis didn't reveal any association between MnSOD rs4880 polymorphism and PE in Asians, Caucasians, or Middle Easterners.

CONCLUSIONS

This meta-analysis shows a significant association between the EPHX1 rs1051740 and PE risk in Caucasians. Meantime, there was a statistically significant association between EPHX1 rs2234922 polymorphism and PE in Middle Easterners.

An epoxide hydrolase from endophytic Streptomyces shows unique structural features and wide biocatalytic activity

The genus Streptomyces is characterized by the production of a wide variety of secondary metabolites with remarkable biological activities and broad antibiotic capabilities. The presence of an unprecedented number of genes encoding hydrolytic enzymes with industrial appeal such as epoxide hydrolases (EHs) reveals its resourceful microscopic machinery. The whole-genome sequence of Streptomyces sp. CBMAI 2042, an endophytic actinobacterium isolated from Citrus sinensis branches, was explored by genome mining, and a putative α/β-epoxide hydrolase named B1EPH2 and encoded by 344 amino acids was selected for functional and structural studies. The crystal structure of B1EPH2 was obtained at a resolution of 2.2 Å and it was found to have a similar fold to other EHs, despite its hexameric quaternary structure, which contrasts with previously solved dimeric and monomeric EH structures. While B1EPH2 has a high sequence similarity to EHB from Mycobacterium tuberculosis, its cavity is similar to that of human EH. A group of 12 aromatic and aliphatic racemic epoxides were assayed to determine the activity of B1EPH2; remarkably, this enzyme was able to hydrolyse all the epoxides to the respective 1,2-diols, indicating a wide-range substrate scope acceptance. Moreover, the (R)- and (S)-enantiomers of styrene oxide, epichlorohydrin and 1,2-epoxybutane were used to monitor enantiopreference. Taken together, the functional and structural analyses indicate that this enzyme is an attractive biocatalyst for future biotechnological applications.

Genetic and clinical risk factors associated with phenytoin-induced cutaneous adverse drug reactions in Thai population

OBJECTIVE

This study aimed to describe the genetic and clinical risk factors associated with phenytoin-induced cutaneous adverse drug reactions (PHT-induced cADRs) in Thai patients.

METHOD

A retrospective case-control study was conducted among 88 PHT- cADRs (25 SJS/TEN, 37 DRESS/DIHS and 26 MPE) compared to 70 PHT-tolerant controls during 2008-2017. Genotyping was performed by Taqman RT-PCR (EPHX1 337 T > C, EPHX1 416A > G and CYP2C9*3), pyrosequencing (UGT1A1*28, UGT1A1*6) and polymerase chain reaction-sequence-specific oligonucleotide probe (HLA-B). Chi-squared test and binary logistic regression were used to identify factors associated with PHT-cADRs.

RESULTS

Multivariate analysis showed that HLA-B*46:01 was significantly associated with all PHT-induced cADRs (OR 2.341; 95% CI, 1.078-5.084; P = .032). Age of ≥60 years showed a significant association with PHT-induced SJS/TEN (OR 3.600; 95% CI, 1.214-10.672; P = .021). CYP2C9*3 was almost reaching statistically associated with an increased risk of PHT-induced SJS/TEN (OR 4.800; 95% CI, 0.960-23.990; P = .056). While HLA-B*56:02/04 was found to have a significant association with PHT-induced DRESS/DIHS (OR 29.312; 95% CI, 1.213-707.994; P = .038). Moreover, female gender and HLA-B*40:01 were associated with an increased risk of PHT-induced MPE at OR 5.734; 95% CI, 0.910-58.351; P = .042 and OR 3.647; 95% CI, 1.193-11.147; P = .023, respectively.

CONCLUSION

Both clinical (advanced age, female gender) and genetic factors (HLA-B*46:01, CYP2C9*3, HLA-B*56:02/04 and HLA-B*40:01) contributed to the risk of PHT-induced cADRs. Further studies with larger sample size may be warranted to confirm these findings and also the influence of EPHX1 gene.

Exploring Solanum tuberosum Epoxide Hydrolase Internal Architecture by Water Molecules Tracking

Several different approaches are used to describe the role of protein compartments and residues in catalysis and to identify key residues suitable for the modification of the activity or selectivity of the desired enzyme. In our research, we applied a combination of molecular dynamics simulations and a water tracking approach to describe the water accessible volume of Solanum tuberosum epoxide hydrolase. Using water as a molecular probe, we were able to identify small cavities linked with the active site: (i) one made up of conserved amino acids and indispensable for the proper positioning of catalytic water and (ii) two others in which modification can potentially contribute to enzyme selectivity and activity. Additionally, we identified regions suitable for de novo tunnel design that could also modify the catalytic properties of the enzyme. The identified hot-spots extend the list of the previously targeted residues used for modification of the regioselectivity of the enzyme. Finally, we have provided an example of a simple and elegant process for the detailed description of the network of cavities and tunnels, which can be used in the planning of enzyme modifications and can be easily adapted to the study of any other protein.

Anti-tubercular activity of a natural stilbene and its synthetic derivatives

Objectives: Tuberculosis (TB) and multidrug- and extensively drug-resistant TB in particular are remaining a major global health challenge and efficient new drugs against TB are needed. This study evaluated the anti-tubercular activity of a natural stilbene and its synthetic derivatives against M. tuberculosis.

Methods: Isopropylstilbene and its synthetic derivatives were analyzed for their anti-tubercular activity against M. tuberculosis ATCC 27294 as well as multidrug- and extensively drug-resistant M. tuberculosis clinical isolates by using MGIT 960 instrumentation and EpiCenter software equipped with TB eXiST module. Cytotoxic effects of drug candidates were determined by a MTT dye reduction assay using A549 adenocarcinomic human alveolar basal epithelial cells.

Results: Growth of M. tuberculosis ATCC 27294 was suppressed by the natural isopropylstilbene HB64 as well as synthetic derivatives DB56 and DB55 at 25 µg/ml. Growth of clinical isolates MDR and XDR M. tuberculosis was suppressed by HB64 at 100 µg/ml as well as by synthetic derivatives DB56 and DB55 at 50 µg/ml and 25 µg/ml, respectively. No anti-tubercular activity was demonstrated for synthetic derivatives DB53, EB251, and RB57 at 100 µg/ml. Toxicity in terms of IC₅₀ values of HB64, DB55 and DB56 were 7.92 µg/ml, 12.15 µg/ml and 16.01 µg/ml, respectively.

Conclusions: Synthetical derivatives of stilbene might be effective candidates as anti-tubercular drugs. However, toxicity of these substances as determined by IC₅₀ values might limit therapeutic success in vivo. Further investigations should address lowering the toxicity for parenteral administration by remodeling stilbene derivatives.

Identification and induction of cytochrome P450s involved in the metabolism of flavone-8-acetic acid in mice

The metabolism of flavone-8-acetic acid (FAA) has been hypothesized to be partly responsible for its potent anticancer activity in mice. The purpose of this study was to identify the mouse enzymes involved in FAA Phase I metabolism and evaluate their possible induction in vivo by FAA. Mouse microsomes metabolized FAA into 6 metabolites: 3',4'-dihydrodiol-FAA, 5,6-epoxy-FAA, 4'-OH-FAA, 3'-OH-FAA, 3',4'-epoxy-FAA and 6-OH-FAA. Using Cyp-specific inhibitors (furafylline, Cyp1a2; α-naphthoflavone, Cyp1b1; tranylcypromine, Cyp2b9; quercetin, Cyp2c29; quinidine, 2d9; diethyldithiocarbamate, Cyp2e1; ketoconazole, Cyp3a11), the formation of 5,6-epoxy-FAA was mainly attributed to Cyps 1a2, 1b1, 2b9, 2c29 and 2e1, whereas the 3',4'-epoxy-FAA was formed by Cyps 2b9 and 3a11. The 4'-OH-FAA was generated by Cyps 1a2, 1b1, 2b9 and 2e1, and the 6-OH-FAA was formed by Cyps 1b1 and 2c9. Using the epoxide scavenger N-acetyl cysteine, 4'-OH-FAA, 3'-OH-FAA and 6-OH-FAA were shown to derive partly from non enzymatic isomerisation of their corresponding epoxides. The specific epoxide hydrolase inhibitor elaidamide allowed the confirmation that 3',4'-dihydrodiol-FAA was formed via the epoxide hydrolase. FAA treatment in vivo in mice led to a significant increase in the hepatic expression of Cyp1a2 (1.9-fold), 2e1 (2.1-fold), 2b10 (3.2-fold), 2d9 (2.3-fold) and 3a11 (2.2-fold), as evaluated by qRT-PCR. In conclusion, several Cyps were shown to be involved in FAA metabolism, particularly Cyps 3a11 and 2b9 which were responsible for the formation of the principal metabolites (5,6-epoxy-FAA, 3',4'-epoxy-FAA), and that FAA could induce the expression of several Cyps after in vivo administration. The possible implication of these enzymes in the in vivo anticancer activity of FAA in mice is discussed.

Purification, crystallization and preliminary X-ray diffraction analysis of Cif, a virulence factor secreted by Pseudomonas aeruginosa

The opportunistic pathogen Pseudomonas aeruginosa secretes a protein that triggers the accelerated degradation of the cystic fibrosis transmembrane conductance regulator (CFTR) in airway epithelial cells. This protein, which is known as the CFTR inhibitory factor (Cif), acts as a virulence factor and may facilitate airway colonization by P. aeruginosa. Based on sequence similarity Cif appears to be an epoxide hydrolase (EH), but it lacks several of the conserved features found in the active sites of canonical members of the EH family. Here, the crystallization of purified recombinant Cif by vapor diffusion is reported. The crystals formed in space group C2, with unit-cell parameters a = 167.4, b = 83.6, c = 88.3 A, beta = 100.6 degrees . The crystals diffracted to 2.39 A resolution on a rotating-anode source. Based on the calculated Matthews coefficient (2.2 A(3) Da(-1)), it appears that the asymmetric unit contains four molecules.

Cloning, expression, purification, crystallization and preliminary X-ray studies of epoxide hydrolases A and B from Mycobacterium tuberculosis

Mycobacterium tuberculosis epoxide hydrolases A and B, corresponding to open reading frames Rv3617 and Rv1938, are detoxification enzymes against epoxides. The recombinant forms of these enzymes have been expressed in Escherichia coli and purified to homogeneity. Diffraction-quality crystals of Rv3617 and Rv1938 were obtained by the hanging-drop vapour-diffusion technique. Crystals of Rv3617 and Rv1938 diffracted to 3.0 and 2.1 A resolution, respectively, at the ALS synchrotron at Berkeley, CA, USA.