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Female offspring of Sprague-Dawley rats fed a high-salt diet (HS) during pregnancy show an enhancement of mean arterial pressure (MAP) and heart rate (HR) response to acute stress in adulthood compared to offspring whose mothers were fed a normal-salt diet (NS) [1]. In the present study, we first examined the expression of soluble epoxide hydrolase (SEH) protein in brain tissue. Whole brains were collected and SEH gene (EPHX2) mRNA and SEH protein expression were analyzed using RT-PCR and Western blot, respectively. mRNA levels were relatively decreased in high-salt rats (1.0 ± 0.32 NS vs 0.39 ± 0.07 HS, n=6). However, the relative expression of SEH protein was significantly increased in HS rats (0.97 ± 0.06 NS vs. 1.72 ± 0.32 HS, n=10). SEH is an enzyme that inactivates epoxyeicosatrienoic acids (EETs), which can increase the level of oxygen free radical production and potentially produce an increase in blood pressure. Tempol, a free radical scavenger, was administered ntracerebroventricularly to HS (n=12) and NS (n=11) offspring to determine if the stressinduces cardiovascular hyperresponsiveness could be reversed. We were unable to conclusively show that this was the case. Hence, the expression of SEH protein in the brains of HS offspring was increased, but a role, if any, for this change in explaining the exaggerated response to acute stress remains elusive. Second, the expression of the glucocorticoid receptor (GR) gene was investigated. We focused on the methylation patterns of the exon 17 GR promoter and 17 CpG dinucleotide sites that include the NGFI-A transcription factor binding site. Female rats (HS n=8, NS n=8) were sacrificed and brains were immediately extracted. Tissue from the pituitary, hypothalamus, and hippocampus was removed and DNA was extracted from each of these areas. CT conversion was performed on the DNA samples followed by cloning and sequencing. Methylation patterns between HS and NS in the pituitary, hypothalamus, and hippocampus did not vary. RT-PCR and Western blot were performed to investigate differences in the levels of GR transcription and/or translation. There were no significant differences found. However, the trends found may suggest different levels of GR mRNA and protein between HS and NS female rats. DNA methylation may play a role in the regulation of GR in prenatal high-salt female offspring. Additional studies will be needed to pinpoint the mechanisms responsible for the exaggerated cardiovascular response to acute stress in HS offspring.

L’époxyde hydrolase soluble (sEH) est une enzyme ubiquitaire, bifonctionnelle, codée par le gène EPHX2. La partie hydrolase (sEH-H) est responsable de la dégradation de facteurs endothéliaux vasodilatateurs, les acides époxyeicosatriénoïques (EETs), alors que la partie phosphatase (sEH-P) est impliquée dans le métabolisme des acides lysophosphatidiques (LPAs).L’objectif de ce travail a été de développer des outils méthodologiques permettant d'évaluer le rôle de la sEH dans la physiopathologie des maladies cardiovasculaires.Nous avons développé une méthode de quantification par CLHP-MS² des EETs et de leurs métabolites, les acides dihydroxyeicosatrienoic acids (DHETs). L'application de cette méthode montre que la dysfonction endothéliale des patients atteints d’hypertension artérielle et de diabète de type 2 est associée à une diminution de la libération locale des EETs lors de l'augmentation du débit sanguin, notamment liée à une augmentation d’activité de la sEH-H. L’inhibition pharmacologique de la sEH-H a permis de diminuer l’inflammation et l’atteinte glomérulaire dans un modèle murin d’insulino-résistance. De plus, l’étude des polymorphismes génétiques du gène EPHX2, codant la sEH, a permis de démontrer que la fonction sEH-H joue probablement un rôle important dans le contrôle de la fonction rénale et vasculaire des patients transplantés rénaux. Enfin, les résultats expérimentaux obtenus dans un modèle d’inactivation génétique de la sEH-P et l'étude des polymorphismes génétiques d'EPHX2 chez les patients insuffisants cardiaques suggèrent un rôle important de cette partie dans la régulation du métabolisme des lipides ainsi que dans le contrôle de l’homéostasie cardiovasculaire.Ainsi, les résultats obtenus au cours de ce travail soutiennent l’intérêt de développer des inhibiteurs pharmacologiques de la sEH-H pour traiter les maladies cardiovasculaires, rénales et métaboliques chez l’homme et suggèrent que la modulation de la sEH-P pourrait également constituer une nouvelle cible d'intérêt dans la prise en charge de ces pathologies. / Soluble epoxide hydrolase (sEH) is an ubiquitous bifunctional enzyme that is encoded by the EPHX2 gene. The hydrolase activity (sEH-H) is responsible for the conversion of the endothelial vasodilator epoxyeicosatrienoic acids whereas the phosphatase activity (sEH-P) is involved in the metabolism of lysophosphatidic acids (LPAs).The aim of this work was to develop chromatographic methods and molecular biology techniques to evaluate sEH activities in cardiovascular diseases.We developed a LC-MS/MS method to quantify EETs and their metabolites, the dihydroxyeicosatrienoic acids (DHETs). Using this method, we showed that the endothelial dysfunction of hypertensive and type 2 diabetic patients is associated with a decrease in the local production of EETs during flow increase notably due to increased sEH-H activity. In a murine model of insulin resistance, pharmacological inhibition of sEH-H improved renal function by decreasing inflammation, oxidative stress and glomerular lesions. Moreover, genetic investigations of EPHX2 revealed that sEH-H may play a substantial role in the control of renal and vascular function in kidney recipients. Finally, experimental results obtained in knock-in sEH-P deficient rats and genetics findings in patients with heart failure strongly suggest that sEH-P is involved in lipid metabolism and cardiovascular homeostasis.Taken together, these results strengthen the interest of developing pharmacological inhibitors of sEH-H to be tested in patients with cardiovascular, renal or metabolic diseases and suggest that the modulation of sEH-P represents a new therapeutic target to treat these pathologies.

Over the course of more than ten years, there has been a significant increase in the approach employed to inhibit the function of soluble epoxide hydrolase (sEH). The phenomenon of upregulating soluble epoxide hydrolase (sEH) has been found to result in a decrease in the ratio of epoxyeicosatrienoic acids (EETs) to dihydroeicosatrienoic acids (DHETs) in the body. This has garnered significant attention due to the diverse biological functions attributed to EETs, including the regulation of vasodilation, neuroprotection, increased fibrinolysis, calcium ion influx, and anti-inflammatory effects. Consequently, there has been a growing interest in developing and discovering sEH inhibitors through chemical syntheses and natural extracts, with the aim of increasing the availability of these anti-inflammatory molecules by reducing their hydrolysis. A comprehensive examination of this project was conducted to explore the inhibitory effects of YMSV, a tetrapeptide derived from the castor bean (Ricinus communis), on sEH, as well as to elucidate its underlying mechanism of action. YMSV was determined to function as a mixed-competitive inhibitor of soluble epoxide hydrolase (sEH), and the interaction between the peptide and the protein resulted in the disruption of the secondary structural composition of sEH. Furthermore, the hydrogen bond interactions between YMSV and the Asp 333 residue in the active region of soluble epoxide hydrolase (sEH) were demonstrated using molecular docking investigations. However, quantitative structure-activity relationship (QSAR) research revealed that nonpolar, hydrophobic, and bulky amino acids are favored at the N- and C- terminals of peptides for sEH inhibition. The results of this study indicate that peptides obtained from dietary sources possess unique characteristics as inhibitors of soluble epoxide hydrolase (sEH), displaying significant potency. Consequently, these peptides have promise for further development as therapeutic medicines targeting inflammation and depression in the future.

Introduction: Epoxyeicosatrienoic acids (EETs) are converted by the enzyme soluble epoxid hydrolase (sEH) to the biologically inactive dihydroxyeicosatrienoic acids (DHETs). EETs are significantly involved in the control of blood pressure, they influence vascular tone and renal transport mechanism. sEH inhibitor reduce blood pressure by increasing the bioavailability of EETs in many models of hypertension. Aim of the study: To determine that sEH inhibitor decreases blood pressure and improves the renal function during the development of malignant hypertension in transgenic rats after the induction of the mouse renin gene. Methods: Hypertension in Cyp1a1-Ren-2 transgenic rats was induced through a dietary administration of the natural xenobiotic indole-3-carbinol (I3C, 0.3 %) for 3 and 11 days. I3C activates the renin gene. At the same time, during a three-day induction of hypertension, the inhibitor of nitric oxide synthase L-NAME (600 mg/l) was administered in drinking water. The sEH inhibitor c-AUCB was given in drinking water at a dose of 13 or 26 mg/l, starting 48 hours before the initiation of I3C and L-NAME administration. Radiotelemetric measurement of blood pressure was performed and renal excretory parameters were monitored in the conscious animals. The effects on renal hemodynamics and...

Introduction: Two major product groups originate from the arachidonic acid metabolic pathway of cytochromes P450: epoxyeicosatrienoic acid (EETs) and 19 and 20-hydroxyeicosatetraenoic acid (19- and 20-HETE). These metabolites play an important role in the regulation of blood pressure, inflammatory responses, regulation of sodium excretion and other crucial physiological processes. Hypothesis: Our studies were based on the hypothesis that abnormalities in the production and function of these cytochrome P450 metabolites significantly contribute to the pathophysiology of hypertension development, in particular in the angiotensin II-dependent models. Objective: To investigate if the increased bioavailability of the above-mentioned metabolites in the kidney tissue will result in blood pressure reduction in the ANG II - dependent rat model of hypertension. Methods: The two methods to increase the concentration of EETs was chosen. In the first part of the study, we administered a soluble epoxide hydrolase inhibitor cAUCB [cis-4- [4- (3-adamantan-1-yl- ureido) cyclohexyloxy] benzoic acid, at a dose of 26 mg.l-1 administered in drinking water], an enzyme responsible for inactivation of biologically active forms of EETs. In the second series of the experiments we applied a synthetic EET analogue, called...

Cytochrom P450 (CYP)-Enzyme hydroxylieren und epoxydieren Arachidonsäure (AA) zu bioaktiven Metaboliten wie 20-Hydroxyeicosatetraensäure (20-HETE) und Epoxyeicosatriensäuren (EETs). Diese CYP-abhängigen Eicosanoide fungieren als Mediatoren bei der Regulation der Gefäß-, Nieren- und Herzfunktion. Hauptziel der vorliegenden Arbeit war es, die Identität der 20-HETE bildenden CYP-Isoformen in der Mausniere aufzuklären. Ein weiterer Schwerpunkt war die Bestimmung von Veränderungen im Metabolismus CYP-abhängiger Eicosanoide in Tiermodellen des akuten Nieren- und Herzversagens. Zur Identifizierung der 20-HETE bildenden CYP-Isoform wurde die Substrat- und Wirkungsspezifität von Cyp4a10, Cyp4a12a, Cyp4a12b und Cyp4a14, sowie ihre geschlechts- und stammspezifische Expression charakterisiert. Die Ergebnisse dieser Arbeit zeigen, dass Cyp4a12a die 20-HETE Synthase der Mausniere ist. Cyp4a12a wird durch Androgene induziert und seine Expressionshöhe ist für geschlechts- und stammspezifische Unterschiede in der 20-HETE Bildung verantwortlich. Im Rattenmodell des Ischämie/Reperfusions (I/R)-induzierten Nierenschadens wird eine 20-HETE Freisetzung durch I/R induziert. Wir konnten zeigen, dass der I/R-Schaden durch Hemmung der 20-HETE Bildung signifikant reduziert wird. Im Rattenmodell der Herzinsuffizienz (SHHF) ist das Herzversagen mit einer Variante des EPHX2 Gens assoziiert. EPHX2 kodiert für die lösliche Epoxidhydrolase (sEH), die den Abbau von EETs katalysiert. Wir konnten zeigen, dass die Genvariation zu signifikant höheren sEH-Aktivitäten im Herzen (3-fachen) und in der Niere (30-fachen) führt, im Vergleich zu Rattenstämmen, die keine Herzinsuffizienz entwickeln. Die vorliegende Arbeit unterstreicht die pathophysiologische Bedeutung von Veränderungen im Metabolismus von 20-HETE und EETs. Daher erscheint es vielversprechend, den CYP-Eicosanoid Stoffwechsel als neuen Angriffspunkt für die pharmakologische Behandlung kardiovaskulärer Erkrankungen zu erschließen. / Cytochrome P450 (CYP) enzymes hydroxylate and epoxidize arachidonic acid (AA) to bioactive metabolites such as 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs). These CYP-dependent eicosanoids serve as mediators in the regulation of vascular, renal and cardiac function. The main objective of the present study was to identify the 20-HETE producing CYP isoforms in the mouse kidney. Another focus was to determine changes in the metabolism of CYP-dependent eicosanoids in animal models of acute renal and heart failure. To identify the 20-HETE producing CYP-isoform the substrate and reaction specificity of Cyp4a10, Cyp4a12a, Cyp4a12b and Cyp4a14, as well as their sex- and strain-specific expression were characterized. The present study shows that Cyp4a12a is the predominant AA hydroxylase in the mouse kidney. Cyp4a12a is induced by androgens and its expression determines the sex and strain-specific differences in 20-HETE generation. In a rat model of renal ischemia/reperfusion (I/R) injury, I/R triggered the release of 20-HETE and we were able to ameliorate renal injury by pharmacological inhibition of 20-HETE production. In a rat model of heart failure (spontaneously hypertensive heart failure rats, SHHF) the heart failure phenotype is associated with a variant of the EPHX2 gene. EPHX2 is coding for the soluble epoxide hydrolase (sEH) which catalyze the degradation of EETs. We found that the gene variation leads to significantly higher sEH activities in the heart (3-fold) and in the kidney (30-fold) compared to rat strains not prone to the development of heart failure. The present study emphasizes the pathophysiological relevance of changes in the biosynthesis and degradation of 20-HETE and EETs. Therefore, it appears promising to develop the CYP-eicosanoid pathway as a novel clinical target for the treatment of cardiovascular diseases.