A series of N,N′-disubstituted ureas having a conformationally restricted cis-or trans-1,4-cyclohexane α to the urea were prepared and tested as soluble epoxide hydrolase (sEH) inhibitors. This series of compounds showed low nanomolar to picomolar activities against recombinant human sEH. Both isomers showed similar potencies, but the trans isomers were more metabolically stable in human hepatic microsomes. Furthermore, these new potent inhibitors show a greater metabolic stability in vivo than previously described sEH inhibitors. We demonstrated that trans-4-[4-(3-adamantan-1-ylureido)cyclohexyloxy]benzoic acid 13g (t-AUCB, IC 50 = 1.3 ± 0.05 nM) had excellent oral bioavailability (98%, n = 2) and blood area under the curve in dogs and was effective in vivo to treat hypotension in lipopolysaccharide challenged murine models.

Visceral obesity has been defined as an important element of the metabolic syndrome and contributes to the development of insulin resistance and cardiovascular disease. Increasing endogenous levels of epoxyeicosatrienoic acids (EETs) are known for their analgesic, antihypertensive, and antiinflammatory effects. The availability of EETs is limited primarily by the soluble epoxide hydrolase (sEH), which metabolizes EETs to their less active diols. In this study, we tested the hypothesis that EETs are involved in glucose regulation and in retarding the development of insulin resistance. To address the role of EETs in regulating glucose homeostasis and insulin signaling, we used mice with targeted gene deletion of sEH and a subsequent study with a selective sEH inhibitor. When WT mice are fed a high fat diet, insulin resistance develops. However, KO or inhibition of sEH activity resulted in a significant decrease in plasma glucose. These findings are characterized by enhancement of tyrosyl phosphorylation of the insulin receptorand its downstream cascade. In addition, pancreatic islets were larger when sEH was disrupted. This effect was associated with an increase in vasculature. These data suggest that an increase in EETs due to sEH‐gene knockout leads to an increase in the size of islets and improved insulin signaling and sensitivity.

Sumoylation is an important post‐translational modification that provides a rapid and reversible means for controlling the activity, subcellular localization, and stability of target proteins. We have examined the covalent attachment of the small ubiqutin‐like modifier (SUMO) proteins to a consensus sequence ([psi]KXE) on the soluble epoxide hydrolase (EPHX2; sEH) enzyme. This enzyme has epoxide hydrolase activity on the C‐terminal domain and a phosphatase activity on the N‐terminus. Polymorphism in EPHX2 have been recently discovered (K55R) that is associated with risk of incident of coronary heart disease events. Interestingly, features of the sEH N‐terminal catalytic site showing a consensus site for SUMOylation (VKEP) with lysine residue at position 160. This and another human‐specific site of SUMOylation (MKGE with lysine residue at position 55), suggest a post‐translational modification and regulatory mechanism of sEH by SUMOylation. Our primary aim of this study was to determine whether sEH can be in vitro SUMOylated and defines its regulatory role of SUMOylation in its both C and N‐terminus activity. Indeed, SUMOylated process catalyzes the formation of polymeric chains of SUMO‐2 and SUMO‐3 on sEH in vitro, and was detected in vivo. We also identified the SUMOylated site on the sEH sequence and revealed its regulatory mechanism. Supported by NIEHS Grant R37 ES02710, NIEHS SBRP Grant P42 ES04699.

Earlier sEH inhibitors such as AUDA are effective anti‐hypertensive and anti‐inflammatory agents in multiple animal models. However, their poor metabolic stability and water solubility make them difficult to use pharmacologically. For obtaining a compound easy to use in vivo, we present the PK profiles of four conformation‐restricted sEH inhibitors and anti‐inflammatory efficacy of the most promising one.Better PK parameters (higher Cmax, longer t1/2, and greater AUC) were obtained from the four tested inhibitors than AUDA with t‐AUCB showing the best result. Oral bioavailability of t‐AUCB (0.1 mg kg−1) was 75±12% (n=4). Furthermore, when mice were administrated t‐AUCB in drinking water at 4 mg L−1, a fairly stable blood concentration of ~70 nM t‐AUCB was maintained since one day administration, and was totally cleared from blood after 3 days of drug withdrawal. Finally, oral gavage of 0.5 and 1.0 mg kg−1 t‐AUCB were effectively anti‐inflammatory evidenced by reversing LPS‐induced hypotension in a dose‐dependent manner, and significantly shifting the ratio of lipid epoxides to corresponding diols in plasma. t‐AUCB appears around 10 times more orally active than AUDA in this model. Thus t‐AUCB is promising for further in vivo studies related to the biology of sEH and its potential therapeutic applications.