Discovery of novel drug candidates for inhibition of soluble epoxide hydrolase of arachidonic acid cascade pathway implicated in atherosclerosis

Evaluation of the Therapeutic Potential of Sulfonyl Urea Derivatives as Soluble Epoxide Hydrolase (sEH) Inhibitors

The inhibition of soluble epoxide hydrolase (sEH) can reduce the level of dihydroxyeicosatrienoic acids (DHETs) effectively maintaining endogenous epoxyeicosatrienoic acids (EETs) levels, resulting in the amelioration of inflammation and pain. Consequently, the development of sEH inhibitors has been a prominent research area for over two decades. In the present study, we synthesized and evaluated sulfonyl urea derivatives for their potential to inhibit sEH. These compounds underwent extensive in vitro investigation, revealing their potency against human and mouse sEH, with 4f showing the most promising sEH inhibitory potential. When subjected to lipopolysaccharide (LPS)-induced acute lung injury (ALI) in studies in mice, compound 4f manifested promising anti-inflammatory efficacy. We investigated the analgesic efficacy of sEH inhibitor 4f in a murine pain model of tail-flick reflex. These results validate the role of sEH inhibition in inflammatory diseases and pave the way for the rational design and optimization of sEH inhibitors based on a sulfonyl urea template.

Multi-Omic Analysis in a Metabolic Syndrome Porcine Model Implicates Arachidonic Acid Metabolism Disorder as a Risk Factor for Atherosclerosis

Background

The diet-induced gut microbiota dysbiosis has been suggested as a major risk factor for atherothrombosis, however, the detailed mechanism linking these conditions is yet to be fully understood.

Methods

We established a long-term excessive-energy diet-induced metabolic syndrome (MetS) inbred Wuzhishan minipig model, which is characterized by its genetic stability, small size, and human-like physiology. The metabolic parameters, atherosclerotic lesions, gut microbiome, and host transcriptome were analyzed. Metabolomics profiling revealed a linkage between gut microbiota and atherothrombosis.

Results

We showed that white atheromatous plaque was clearly visible on abdominal aorta in the MetS model. Furthermore, using metagenome and metatranscriptome sequencing, we discovered that the long-term excessive energy intake altered the local intestinal microbiota composition and transcriptional profile, which was most dramatically illustrated by the reduced abundance of SCFAs-producing bacteria including Bacteroides, Lachnospiraceae, and Ruminococcaceae in the MetS model. Liver and abdominal aorta transcriptomes in the MetS model indicate that the diet-induced gut microbiota dysbiosis activated host chronic inflammatory responses and significantly upregulated the expression of genes related to arachidonic acid-dependent signaling pathways. Notably, metabolomics profiling further revealed an intimate linkage between arachidonic acid metabolism and atherothrombosis in the host-gut microbial metabolism axis.

Conclusions

These findings provide new insights into the relationship between atherothrombosis and regulation of gut microbiota via host metabolomes and will be of potential value for the treatment of cardiovascular diseases in MetS.

Transcriptome Analysis Provides Insights into Hepatic Responses to Trichloroisocyanuric Acid Exposure in Goldfish (Carassius auratus)

Simple Summary

Trichloroisocyanuric acid (TCCA) has been widely used in public health and aquaculture for the prevention and treatment of diseases. As a strong oxidative disinfectant, TCCA may cause adverse influences on aquatic organisms and further poses a threat to the aquatic ecosystems. Nonetheless, the toxicological influences of TCCA on aquatic animals are still scarce and the mechanisms of the toxicity at the molecular levels in goldfish (Carassius auratus) have not been illustrated. The current study investigated the influences of sublethal concentration of TCCA on transcriptomic responses, the molecular indices of oxidative stress, and histopathological alterations in the hepatic and gill tissues of goldfish. The results indicated that TCCA exposure induced the disturbance of energy metabolism and the detoxification process. Furthermore, TCCA exposure also induced oxidative stress in the liver and caused pathological damage in gills. These findings could be useful to help understand the toxicological influences of TCCA on goldfish.

Abstract

In this study, goldfish (Carassius auratus) were exposed to 0 (control group) and 0.81 mg/L TCCA for four consecutive days. The liver transcriptome, the molecular indices of oxidative stress, and gills histopathology were investigated. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that energy metabolism-related pathways such as glycolysis/gluconeogenesis were significantly enriched, suggesting their perturbation in the liver of goldfish. Additionally, TCCA exposure also caused pathological damage in gills, which compromised physiological function and decreased oxygen intake capacity of gills, thus leading to the enhancement of anaerobic metabolism. This finding was confirmed by the significant upregulation of lactate dehydrogenase in the liver of goldfish. Moreover, many phase I and phase II metabolic enzymes might be activated to alleviate TCCA-induced toxicity in goldfish, and glutathione S-transferases (GSTs) and cytochrome P450s (CYPs) play a crucial role in the metabolism of TCCA in the liver of goldfish. Furthermore, the antioxidant enzyme analysis showed that TCCA exposure induced oxidative damage in the liver and partially impaired the antioxidant defense system of goldfish, evidenced by decreased superoxide dismutase (SOD) and catalase (CAT), and increased malondialdehyde (MDA) level. In summary, this study will improve our understanding of the molecular mechanisms of the TCCA-induced toxicity in goldfish.

A clinical perspective of soluble epoxide hydrolase inhibitors in metabolic and related cardiovascular diseases

Epoxide hydrolase (EH) is a crucial enzyme responsible for catabolism, detoxification, and regulation of signaling molecules in various organisms including human beings. In mammals, EHs are classified according to their DNA sequence, sub-cellular location, and activity into eight major classes: soluble EH (sEH), microsomal EH (mEH), leukotriene A4 hydrolase (LTA4H), cholesterol EH (ChEH), hepoxilin EH, paternally expressed gene 1 (peg1/MEST), EH3 and EH4. The sEH, an α/β-hydrolase fold family enzyme is an emerging pharmacological target in multiple diseases namely, cardiovascular disease, neurodegenerative disease, chronic pain, fibrosis, diabetes, pulmonary diseases, and immunological disease. It exhibits prominent physiological effect that includes anti-inflammatory, anti-migratory and vasodilatory effects. Its efficacy has been documented in several kinds of clinical trials and observational studies. This review specifically highlights the development of soluble epoxide hydrolase inhibitors (sEHIs) in the clinical setting for the management of metabolic syndrome and related disorders such as cardiovascular effects, endothelial dysfunction, arterial disease, hypertension, diabetes, obesity, heart failure, and dyslipidemia. In addition, limitations and future aspects of sEHIs have also been highlighted which will help the investigators to bring the sEHI to the clinics.

Discovery of novel heterocyclic amide-based inhibitors: an integrative in-silico approach to targeting soluble epoxide hydrolase

Inhibition of soluble epoxide hydrolase (sEH) is considered as an emerging druggable target to reduce blood pressure, improve insulin sensitivity, and decrease inflammation. Despite the availability of different classes of sEH small molecule inhibitors for the potential treatment of hypertension, only a few candidates have reached clinical trials, making the optimal control of blood pressure presently unattainable. This necessity motivated us to explore a series of novel quinazoline-4(3H)-one and 4,6-disubstituted pyridin-2(1H)-one derivatives targeting sEH enzyme. Herein, comprehensive computational investigations were performed to probe the inhibition efficacy of these potent compounds in terms of inhibitor-enzyme interactions against sEH. In this study, the 39 in-house with a focused library comprising 39 in-house synthesized compounds were selected. The structure-based pharmacophore modeling was developed based on the crystal structure of sEH with its co-crystallized biologically active inhibitor. The generated hypotheses were applied for virtual screening-based PHASE fitness scores. Docking-based virtual screening workflows were used to generate lead compounds using HTVS, SP and XP based GLIDE G-score values. The candidate leads were filtered using ADMET pharmacological and physicochemical properties screening. A 100-ns of molecular dynamics simulations with Molecular dynamics simulations (100 ns) were performed to explore the binding affinities of the considered compounds. Our study identified four best candidates from quinazoline-4(3H)-one derivatives, which indicated that a quinazolinone ring serves as a suitable scaffold to develop novel small molecule sEH inhibitors.

Endothelial Nox4 dysfunction aggravates atherosclerosis by inducing endoplasmic reticulum stress and soluble epoxide hydrolase

BACKGROUND AND AIMS

Our previous findings have demonstrated the protective effect of endothelial Nox4-based NADPH oxidase on atherosclerosis. One of the possible mechanisms is the inhibition of soluble epoxide hydrolase (sEH), a proinflammatory and atherogenic factor. Our goal was to investigate whether in vivo inhibition of sEH by 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU) alleviates endothelial Nox4 dysfunction caused atherosclerosis and the regulatory mechanism of endothelial Nox4 on sEH.

METHODS

& results: We used endothelial human Nox4 dominant-negative (EDN) transgenic mice in ApoE deficient background to mimic the dysfunction of endothelial Nox4 in atherosclerosis-prone conditions. In EDN aortic endothelium, sEH and the inflammatory marker vascular cell adhesion molecule 1 (VCAM1) were upregulated. TPPU reduced atherosclerotic lesions in EDN mice. In EDN endothelial cells (ECs), the endoplasmic reticulum (ER) stress markers (BIP, IRE1α, phosphorylation of PERK, ATF6) were upregulated, and they can be suppressed by ER stress inhibitor 4-phenyl butyric acid (4-PBA). In EDN ECs, 4-PBA downregulated the expression of sEH and VCAM1, suppressed inflammation, and its application in vivo reduced atherosclerotic lesions of EDN mice.

CONCLUSIONS

Endothelial Nox4 dysfunction upregulated sEH to enhance inflammation, probably by its induction of ER stress. Inhibition of ER stress or sEH is beneficial to alleviate atherosclerosis caused by endothelial Nox4 dysfunction.

Discovery of Soluble Epoxide Hydrolase Inhibitors from Chemical Synthesis and Natural Products

Soluble epoxide hydrolase (sEH) is an α/β hydrolase fold protein and widely distributed in numerous organs including the liver, kidney, and brain. The inhibition of sEH can effectively maintain endogenous epoxyeicosatrienoic acids (EETs) levels and reduce dihydroxyeicosatrienoic acids (DHETs) levels, resulting in therapeutic potentials for cardiovascular, central nervous system, and metabolic diseases. Therefore, since the beginning of this century, the development of sEH inhibitors is a hot research topic. A variety of potent sEH inhibitors have been developed by chemical synthesis or isolated from natural sources. In this review, we mainly summarized the interconnected aspects of sEH with cardiovascular, central nervous system, and metabolic diseases and then focus on representative inhibitors, which would provide some useful guidance for the future development of potential sEH inhibitors.

High-throughput virtual screening of novel potent inhibitor(s) for Human Vanin-1 enzyme

Vanin-1 (VNN1) is a glycosylphosphatidylinositol (GPI)-anchored ectoenzyme which hydrolyzes pantetheine to pantothenic acid and cysteamine. It has emerged as a promising drug target for many human diseases associated with oxidative stress and inflammatory pathways. In the present study we used structure-based virtual screening approach for the identification of small molecule inhibitors of vanin-1. A chemical library consisting of natural compounds, synthetic compounds and RRV analogs were screened for drug-like molecules. The filtered molecules were subjected to molecular docking studies. Three potential hits-ZINC04073864 (Natural compound), CID227017 (synthetic compound) and CID129558381 (RRV analog)-were identified for the target enzyme. The molecules form good number of hydrogen bonds with the catalytic residues such as Glu79, Lys178 and Cys211. The apo-VNN1 and VNN1-ligand complexes were subjected to molecular dynamics (MD) simulation for 30 ns. The geometric properties such as root mean square deviation, radius of gyration, solvent accessible surface area, number of hydrogen bonds and the distance between the catalytic triad residues-Glu79, Lys178 and Cys211 were altered upon binding of the compounds. Essential dynamics and entropic studies further confirmed that the fluctuations in VNN1 decrease upon binding of the compounds. The lead molecules were stable throughout the simulation time period. Molecular Mechanics Poisson-Boltzmann Surface Area (MM/PBSA) studies showed that Van der Waals interaction energy contributes significantly to the total binding free energy. Thus, our study reveals three lead molecules-ZINC04073864, CID227017 and CID129558381 as potential inhibitors of Vanin-1 which can be validated through further studies. Communicated by Ramaswamy H. Sarma.

Soluble Epoxide Hydrolase Inhibition in Liver Diseases: A Review of Current Research and Knowledge Gaps

Emerging evidence suggests that soluble epoxide hydrolase (sEH) inhibition is a valuable therapeutic strategy for the treatment of numerous diseases, including those of the liver. sEH rapidly degrades cytochrome P450-produced epoxygenated lipids (epoxy-fatty acids), which are synthesized from omega-3 and omega-6 polyunsaturated fatty acids, that generally exert beneficial effects on several cellular processes. sEH hydrolysis of epoxy-fatty acids produces dihydroxy-fatty acids which are typically less biologically active than their parent epoxide. Efforts to develop sEH inhibitors have made available numerous compounds that show therapeutic efficacy and a wide margin of safety in a variety of different diseases, including non-alcoholic fatty liver disease, liver fibrosis, portal hypertension, and others. This review summarizes research efforts which characterize the applications, underlying effects, and molecular mechanisms of sEH inhibitors in these liver diseases and identifies gaps in knowledge for future research.