Neuroinflammation is widely recognized as a key pathological hallmark of Alzheimer's disease (AD). Recently, inhibiting soluble epoxide hydrolase (sEH) has emerged as a promising therapeutic strategy for AD. sEH plays a pivotal role in neuroinflammation by hydrolyzing epoxyeicosatrienoic acids (EETs), which have anti-inflammatory and neuroprotective properties, into pro-inflammatory dihydroepoxyeicosatrienoic acids (DHETs). Furthermore, the overexpression of the enzyme in the brains of AD patients and animal models of the disease highlights its relevance as a therapeutic target. Our previous studies, using the inhibitor UB-SCG-51 demonstrated that sEH inhibition regulates neuroinflammation and other mechanisms, such as the unfolded protein response pathway, while reducing autophagy, apoptosis, and neuronal death, thereby promoting neuroprotection. Building on these findings, we evaluated the arginine salt of the compound, designated UB-SCG-74, which offers improved oral absorption compared to that of UB-SCG-51 while retaining high permeability, potency, and selectivity. In experiments using 5XFAD mice, UB-SCG-74 treatment significantly improved cognition and synaptic plasticity, outperforming donepezil, a standard AD drug, and ibuprofen, an anti-inflammatory drug. Remarkably, these benefits persisted for 4 weeks after administration cessation, suggesting lasting therapeutic effects. Safety pharmacology studies showed no toxicity, supporting the advancement of UB-SCG-74 into preclinical regulatory evaluation. Our findings further indicate that sEH inhibition engages multiple neuroprotective pathways, potentially modifying both AD symptoms and disease progression, thus reinforcing its therapeutic potential.

BACKGROUND:Neuroinflammation is widely recognized as a significant hallmark of Alzheimer's disease (AD). To combat neuroinflammation, the inhibition of the soluble epoxide hydrolase (sEH) enzyme has been demonstrated crucial. Importantly, sEH inhibition could be related to other neuroprotective pathways described in AD.AIMS:The aim of the study was to unveil new molecular pathways driving neuroprotection through sEH, we used an optimized, potent, and selective sEH inhibitor (sEHi, UB-SCG-51).MATERIALS AND METHODS:UB-SCG-51 was tested in neuroblastoma cell line, SH-SY5Y, in primary mouse and human astrocytes cultures challenged with proinflammatory insults and in microglia cultures treated with amyloid oligomers, as well as in mice AD model (5XFAD).RESULTS:UB-SCG-51 (10 and 30 μM) prevented neurotoxic reactive-astrocyte conversion in primary mouse astrocytes challenged with TNF-α, IL-1α, and C1q (T/I/C) combination for 24 h. Moreover, in microglial cultures, sEHi reduced inflammation and glial activity. In addition, UB-SCG-51 rescued 5XFAD cognitive impairment, reducing the number of Amyloid-β plaques and Tau hyperphosphorylation accompanied by a reduction in neuroinflammation and apoptotic markers. Notably, a transcriptional profile analysis revealed a new pathway modulated by sEHi treatment. Specifically, the eIF2α/CHOP pathway, which promoted the endoplasmic reticulum response, was increased in the 5XFAD-treated group. These findings were confirmed in human primary astrocytes by combining sEHi and eIF2α inhibitor (eIF2αi) treatment. Besides, combining both treatments resulted in increased in C3 gene expression after T/I/C compared with the group treated with sEHi alone in cultures.DISCUSSION:Therefore, sEHi rescued cognitive impairment and neurodegeneration in AD mice model, based on the reduction of inflammation and eIF2α/CHOP signaling pathway.CONCLUSIONS:In whole, our results support the concept that targeting neuroinflammation through sEH inhibition is a promising therapeutic strategy to fight against Alzheimer's disease with additive and/or synergistic activities targeting neuroinflammation and cell stress.

Epoxyeicosatrienoic acids (EETs) are endogenous chemical mediators that show anti‐inflammatory, antihypertensive, and analgesic effects. Soluble epoxide hydrolase (sEH) converts EETs to their corresponding dihydroxyeicosatrienoic acids, whereby the biological effects of EETs are modified. Therefore, inhibition of sEH has been suggested as a novel pharmacological approach for the treatment of inflammatory and pain‐related disorders.1

The soluble epoxide hydrolase (sEH) has been suggested as a pharmacological target for the treatment of several diseases, including pain-related disorders. Herein, we report further medicinal chemistry around new benzohomoadamantane-based sEH inhibitors (sEHI) in order to improve the drug metabolism and pharmacokinetics properties of a previous hit. After an extensive in vitro screening cascade, molecular modeling, and in vivo pharmacokinetics studies, two candidates were evaluated in vivo in a murine model of capsaicin-induced allodynia. The two compounds showed an anti-allodynic effect in a dose-dependent manner. Moreover, the most potent compound presented robust analgesic efficacy in the cyclophosphamide-induced murine model of cystitis, a well-established model of visceral pain. Overall, these results suggest painful bladder syndrome as a new possible indication for sEHI, opening a new range of applications for them in the visceral pain field.

With innumerable clinical failures of target-specific drug candidates for multifactorial diseases, such as Alzheimer's disease (AD), which remains inefficiently treated, the advent of multitarget drug discovery has brought a new breath of hope. Here, we disclose a class of 6-chlorotacrine (huprine)–TPPU hybrids as dual inhibitors of the enzymes soluble epoxide hydrolase (sEH) and acetylcholinesterase (AChE), a multitarget profile to provide cumulative effects against neuroinflammation and memory impairment. Computational studies confirmed the gorge-wide occupancy of both enzymes, from the main site to a secondary site, including a so far non-described AChE cryptic pocket. The lead compound displayed in vitro dual nanomolar potencies, adequate brain permeability, aqueous solubility, human microsomal stability, lack of neurotoxicity, and it rescued memory, synaptic plasticity, and neuroinflammation in an AD mouse model, after low dose chronic oral administration.

The pharmacological inhibition of soluble epoxide hydrolase (sEH) is efficient for the treatment of inflammatory and pain-related diseases. Numerous potent sEH inhibitors (sEHIs) present adamantyl or phenyl moieties, such as the clinical candidates AR9281 or EC5026. Herein, in a new series of sEHIs, these hydrophobic moieties have been merged in a benzohomoadamantane scaffold. Most of the new sEHIs have excellent inhibitory activities against sEH. Molecular dynamics simulations suggested that the addition of an aromatic ring into the adamantane scaffold produced conformational rearrangements in the enzyme to stabilize the aromatic ring of the benzohomoadamantane core. A screening cascade permitted us to select a candidate for an in vivo efficacy study in a murine model of cerulein-induced acute pancreatitis. The administration of 22 improved the health status of the animals and reduced pancreatic damage, demonstrating that the benzohomoadamantane unit is a promising scaffold for the design of novel sEHIs.

The pharmacological inhibition of soluble epoxide hydrolase (sEH) has been suggested as a potential therapy for the treatment of pain and inflammatory diseases through the stabilization of endogenous epoxyeicosatrienoic acids. Numerous potent sEH inhibitors (sEHI) have been developed, however many contain highly lipophilic substituents limiting their availability. Recently, a new series of benzohomoadamantane-based ureas endowed with potent inhibitory activity for the human and murine sEH was reported. However, their very low microsomal stability prevented further development. Herein, a new series of benzohomoadamantane-based amides were synthetized, fully characterized, and evaluated as sEHI. Most of these amides were endowed with excellent inhibitory potencies. A selected compound displayed anti-inflammatory effects with higher effectiveness than the reference sEHI, TPPU.

Niemann–Pick type C (NPC) disease is a rare autosomal recessive inherited childhood neurodegenerative disease characterized by the accumulation of cholesterol and glycosphingolipids, involving the autophagy-lysosome system. Inhibition of soluble epoxide hydrolase (sEH), an enzyme that metabolizes epoxy fatty acids (EpFAs) to 12-diols, exerts beneficial effects in modulating inflammation and autophagy, critical features of the NPC disease. This study aims to evaluate the effects of UB-EV-52, an sEH inhibitor (sEHi), in an NPC mouse model (Npc) by administering it for 4 weeks (5 mg/kg/day). Behavioral and cognitive tests (open-field test (OF)), elevated plus maze (EPM), novel object recognition test (NORT) and object location test (OLT) demonstrated that the treatment produced an improvement in short- and long-term memory as well as in spatial memory. Furthermore, UB-EV-52 treatment increased body weight and lifespan by 25% and reduced gene expression of the inflammatory markers (i.e., Il-1β and Mcp1) and enhanced oxidative stress (OS) markers (iNOS and Hmox1) in the treated Npc mice group. As for autophagic markers, surprisingly, we found significantly reduced levels of LC3B-II/LC3B-I ratio and significantly reduced brain protein levels of lysosomal-associated membrane protein-1 (LAMP-1) in treated Npc mice group compared to untreated ones in hippocampal tissue. Lipid profile analysis showed a significant reduction of lipid storage in the liver and some slight changes in homogenated brain tissue in the treated NPC mice compared to the untreated groups. Therefore, our results suggest that pharmacological inhibition of sEH ameliorates most of the characteristic features of NPC mice, demonstrating that sEH can be considered a potential therapeutic target for this disease.

In vivo pharmacological inhibition of soluble epoxide hydrolase (sEH) reduces inflammatory diseases, including acute pancreatitis (AP). Adamantyl ureas are very potent sEH inhibitors, but the lipophilicity and metabolism of the adamantane group compromise their overall usefulness. Herein, we report that the replacement of a methylene unit of the adamantane group by an oxygen atom increases the solubility, permeability, and stability of three series of urea-based sEH inhibitors. Most of these oxaanalogues are nanomolar inhibitors of both the human and murine sEH. Molecular dynamics simulations rationalize the molecular basis for their activity and suggest that the presence of the oxygen atom on the adamantane scaffold results in active site rearrangements to establish a weak hydrogen bond. The 2-oxaadamantane 22, which has a good solubility, microsomal stability, and selectivity for sEH, was selected for further in vitro and in vivo studies in models of cerulein-induced AP. Both in prophylactic and treatment studies, 22 diminished the overexpression of inflammatory and endoplasmic reticulum stress markers induced by cerulein and reduced the pancreatic damage.

The inhibition of the enzyme soluble epoxide hydrolase (sEH) has demonstrated clinical therapeutic effects in several peripheral inflammatory-related diseases, with 3 compounds in clinical trials. However, the role of this enzyme in the neuroinflammation process has been largely neglected. Herein, we disclose the pharmacological validation of sEH as a novel target for the treatment of Alzheimer's disease (AD). Evaluation of cognitive impairment and pathological hallmarks were used in 2 models of age-related cognitive decline and AD using 3 structurally different and potent sEH inhibitors as chemical probes. sEH is upregulated in brains from AD patients. Our findings supported the beneficial effects of central sEH inhibition, regarding reducing cognitive impairment, neuroinflammation, tau hyperphosphorylation pathology, and the number of amyloid plaques. This study suggests that inhibition of inflammation in the brain by targeting sEH is a relevant therapeutic strategy for AD.

Soluble epoxide hydrolase (sEH) inhibitors are potential drugs for several diseases. Adamantyl ureas are excellent sEH inhibitors but have limited metabolic stability. Herein, we report the effect of replacing the adamantane group by alternative polycyclic hydrocarbons on sEH inhibition, solubility, permeability and metabolic stability. Compounds bearing smaller or larger polycyclic hydrocarbons than adamantane yielded all good inhibition potency of the human sEH (0.4 ≤ IC50 ≤ 21.7 nM), indicating that sEH is able to accommodate inhibitors of very different size. Human liver microsomal stability of diamantane containing inhibitors is lower than that of their corresponding adamantane counterparts.

Acute pancreatitis (AP) is a serious and life‐threatening inflammatory disease and arises as one of the most common gastrointestinal disorders worldwide. Aside from palliative treatments (analgesics, hydration, antibiotics), there is no standard therapeutic strategy for reducing inflammation in AP.Epoxyeicosatrienoic acids (EETs) are endogenous chemical mediators derived from arachidonic acid that show anti‐inflammatory, antihypertensive, analgesic, angiogenic, and anti‐atherosclerotic effects. Soluble epoxide hydrolase (sEH) converts EETs to their corresponding dihydroxyeicosatrienoic acids, whereby the biological effects of EETs are diminished, eliminated, or altered. It has been proposed that inhibition of sEH may have therapeutic effects in various inflammatory diseases.Recently, it has been studied the effects of pharmacological inhibition of sEH using TPPU, a potent sEH inhibitor (sEHI), on cerulein‐ and arginine‐induced AP murine models. The results showed a reduction of circulating and pancreatic levels of mRNA of different inflammatory cytokines and diminution of the endoplasmic reticulum stress and cell death.Herein we report the synthesis and structure‐activity relationships of a series of novel sEHI with excellent drug‐like properties. Most of them were endowed with low nanomolar or even subnanomolar IC50 values against the human and murine sEH enzyme. They also inhibited the sEH in the rat pancreatic acinar cell line AR42J. Further in vitro profiling (human and mice microsomal stability, solubility, CYP inhibition, selectivity) and pharmacokinetic studies allowed us to select a candidate for an in vivo efficacy study in a mice model of cerulein‐induced AP.We found that our candidate, administered intraperitoneally (3 mg/Kg) after the induction of AP, significantly reduced pancreatic mRNA abundance of the inflammatory cytokines tumor necrosis factor‐α, interleukins Il‐1β, Il‐6 and Il‐10; the enzymes myeloperoxidase, pancreatic amylase and pancreatic trypsin, and the chemokines MCP‐1 and CXC1.In summary, these novel results and the previously reported studies using other sEHI, strongly suggest that sEH may be a target of interest for treating AP.Support or Funding InformationWe thank Ministerio de Economía y Competitividad (Agencia Estatal de Investigación) and Fondo Europeo de Desarrollo Regional (MINECO‐FEDER) (SAF2017‐82771 and SAF2015‐64146‐R7), Generalitat de Catalunya (2017SGR106), Spain EIT Health (Proof of concept 2016) and Fundació Bosch i Gimpera, Universitat de Barcelona (F2I grant) for funding. S.C. thanks the Universitat de Barcelona for a PhD Grant (APIF program). This work was supported in part by the National Institute of Environmental Health Sciences grant R01‐ES002710, and Superfund Research Program P42 ES04699.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Trabajo presentado en la XXV EFMC International Symposium on Medicinal Chemistry (European Federation for Medicinal Chemistry), celebrada en Ljubljana, Slovenia, del 2 al 6 de septiembre de 2018

The metal-catalyzed [2+2+2] cocycloaddition of arynes with pyramidalized alkenes is presented. The generation of a highly reactive pyramidalized alkene in the presence of a large excess of in situ-produced arynes led to the corresponding cocyclotrimerization (1 : 2)-adducts in good yields, establishing the first example of a palladium-based reaction of a pyramidalized alkene.

Epoxyeicosatrienoic acids (EETs) are endogenous chemical mediators derived from arachidonic acid. These EETs show anti‐inflammatory, antihypertensive, analgesic, angiogenic, and antiatherosclerotic effects.1 Soluble epoxide hydrolase (sEH) converts EETs to their corresponding dihydroxyeicosatrienoic acids, whereby the biological effects of EETs are diminished, eliminated, or altered. It has been proposed that inhibition of sEH may have therapeutic effects in various inflammatory diseases. Potent, orally bioavailable sEH inhibitors (sEHI) have been developed, several of them featuring an adamantane scaffold, including AR9281 that proved to be safe in human clinical trials.2Our research group is working in novel sEHI bearing adamantane‐like scaffolds. 2‐oxaadamantane arose as a suitable replacement moiety since the derivatives bearing it maintained the inhibitory activity on the target and increased solubility.3 Herein we report the synthesis and structure‐activity relationships of a series of novel 2‐oxaadamantane‐based ureas with improved drug‐like properties. Several of them reduced the levels of endoplasmic reticulum (ER) stress and inflammatory markers in an in vitro model of cerulein‐induced acute pancreatitis (AP) in the rat pancreatic acinar cell line AR42J. Further in vitro profiling (human and mice microsomal stability, solubility, cytotoxicity, cytochromes inhibition, Caco‐2 permeability, selectivity, hERG inhibition) and pharmacokinetics (PK) and maximum tolerated dose (MTD) studies allowed us to select a candidate for in vivo studies in two mice models of cerulein‐induced AP.4We found that cerulein‐induced AP significantly increased sEH activity,5 and we noted that intraperitoneal administration of our inhibitor restored sEH activity to normality. We found that the sEHI, administered before or after induction of AP, significantly reduced, in a dose‐dependent manner, pancreatic mRNA abundance of the inflammatory cytokines tumor necrosis factor‐α, interleukin Il‐1β and Il‐6, and the chemokine MCP‐1. Additionally, the levels of the ATF‐3 ER stress marker were also reduced in the sEHI‐treated mice.In summary, these results suggest that 2‐oxaadamantane‐based sEHI may be of clinical interest for preventing and treating acute pancreatitis.Support or Funding InformationFinancial support from Ministerio de Economía y Competitividad (Projects SAF2014‐57094‐R and SAF2015‐64146‐R), CaixaImpulse 2015 Programme and Spain EIT Health proof of concept 2016 are acknowledged. R. L. and E. V. thank the Ministerio de Educación, Cultura y Deporte (FPU program), and the IBUB, respectively, for PhD Grants. S.C. and E. P. thank the Universitat de Barcelona for PhD Grants. The authors thank Bruce D. Hammock and Christophe Morisseau (UCD) for advice when we started running up the sEHI assay kit and for stimulating discussions.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Two series of easily accessible anilines were identified as inhibitors of influenza A virus subtype H1N1, and extensive chemical synthesis and analysis of the structure-activity relationship were performed. The compounds were shown to interfere with low pH-induced membrane fusion mediated by the H1 and H5 (group 1) hemagglutinin (HA) subtypes. A combination of virus resistance, HA interaction, and molecular dynamics simulation studies elucidated the binding site of these aniline-based influenza fusion inhibitors, which significantly overlaps with the pocket occupied by some H3 HA-specific inhibitors, indicating the high relevance of this cavity for drug design.

A mild procedure for the direct reaction of aromatic and aliphatic aldehyde bisulfite adducts with primary and secondary amine hydrochlorides in the presence of sodium cyanoborohydride in methanol is reported.