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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., This study was supported by the Ministerio de Economía, Industria y Competitividad (Agencia Estatal de Investigación, AEI) and Fondo Europeo de Desarrollo Regional (MINECO-FEDER) (Projects SAF2017-82771, SAF2016-77703, Fundació La Caixa (project CI18-00002) and SAF2015-68749) and Generalitat de Catalunya (2017 SGR 106). S.C. and E.P. thank the Universitat de Barcelona and the Institute of Biomedicine of the Universitat de Barcelona (IBUB), respectively, for PhD grants. R.L. and D.P.-I. thank the Ministerio de Educación, Cultura y Deporte for PhD grants (FPU program). We would also like to thank Xunta de Galicia (ED431C 2018/21) and Ministerio de Economía, Industria y Competitividad (Innopharma Project) and Fondo Europeo de Desarrollo Regional (MINECO-FEDER). This study was also supported, in part, by grants from the National Institute of Environmental Health Sciences (NIEHS), the RIVER Award, NIEHS/R35 ES030443, and NIEHS Superfund Research Program P42 ES004699. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Impaired glucocorticoid (GC) signaling is a significant factor in aging, stress, and neurodegenerative diseases such as Alzheimer’s disease. Therefore, the study of GC-mediated stress responses to chronic moderately stressful situations, which occur in daily life, is of huge interest for the design of pharmacological strategies toward the prevention of neurodegeneration. To address this issue, SAMP8 mice were exposed to the chronic mild stress (CMS) paradigm for 4 weeks and treated with RL-118, an 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor. The inhibition of this enzyme is linked with a reduction in GC levels and cognitive improvement, while CMS exposure has been associated with reduced cognitive performance. The aim of this project was to assess whether RL-118 treatment could reverse the deleterious effects of CMS on cognition and behavioral abilities and to evaluate the molecular mechanisms that compromise healthy aging in SAMP8 mice. First, we confirmed the target engagement between RL-118 and 11β-HSD1. Additionally, we showed that DNA methylation, hydroxymethylation, and histone phosphorylation were decreased by CMS induction, and increased by RL-118 treatment. In addition, CMS exposure caused the accumulation of reactive oxygen species (ROS)-induced damage and increased pro-oxidant enzymes—as well as pro-inflammatory mediators—through the NF-κB pathway and astrogliosis markers, such as GFAP. Of note, these modifications were reversed by 11β-HSD1 inhibition. Remarkably, although CMS altered mTORC1 signaling, autophagy was increased in the SAMP8 RL-118-treated mice. We also showed an increase in amyloidogenic processes and a decrease in synaptic plasticity and neuronal remodeling markers in mice under CMS, which were consequently modified by RL-118 treatment. In conclusion, 11β-HSD1 inhibition through RL-118 ameliorated the detrimental effects induced by CMS, including epigenetic and cognitive disturbances, indicating that GC-excess attenuation shows potential as a therapeutic strategy for age-related cognitive decline and AD.

1.AbstractTaking into consideration the convergence of ageing, stress and neurodegenerative diseases, such as AD, there is impaired GC signalling. Therefore, the study of GC-mediated stress response to chronic moderate stressful situations, as account in daily life, becomes of huge interest to design pharmacological strategies to prevent neurodegeneration.To address this issue, SAMP8 were exposed for 4 weeks to the CMS paradigm and treated with RL-118, an 11β-HSD1 inhibitor. In fact, several pieces of evidence link the inhibition of this enzyme with reduction of GC levels and cognitive improvement, while CMS exposure has been associated with reduced cognitive performance. The aim of this project was to assess whether RL-118 treatment could restore the deleterious effects of CMS on cognition and behavioural abilities, but also on molecular mechanisms that compromise healthy ageing in SAMP8 mice.On the one hand, we determined the target engagement between RL-118 and 11β-HSD1. Therefore all the beneficial effects previously described in SAMP8 treated with the drug can undoubtedly be attributed to the inhibition of this enzyme. Besides, herein we observed decreased DNA methylation, hydroxymethylation and histone phosphorylation induced by CMS but, on the contrary, increased after RL-118 treatment. In addition, CMS exposure produced ROS damage accumulation, and increments of pro-oxidant enzymes as well as pro-inflammatory mediators through NF-κB pathway and astrogliosis markers, like Gfap. Of note, those modifications were recovered by 11β-HSD1 inhibition. Remarkably, although CMS altered mTORC1 signalling, autophagy was increased in SAMP8 treated with RL-118 mice. Also, we found amyloidogenic APP processing pathway favoured and decreased synaptic plasticity and neuronal remodelling markers in mice under CMS, but changed after RL-118 treatment. In consequence, detrimental effects on behaviour and cognitive performance were detected in CMS exposed mice, but restored after concomitant 11β-HSD1 inhibition by RL-118.Overall, CMS is a feasible intervention to understand the influence of stress on epigenetic mechanisms underlying cognition and accelerating senescence. However and most important, 11β-HSD1 inhibition through RL-118 turned up to restore the majority of these detrimental effects caused by CMS, indicating that GC excess attenuation may become a potential therapeutic strategy for age-related cognitive decline and AD.

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 oxa-analogues 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., This work was funded by the Spanish Ministerio de Economía Industria y Competitividad (grants SAF2017-82771-R to S.V., SAF2015-64146-R, andMICIU/ICTI2017-2020/Referencito M.V.-C., RTI2018-093955-B-C21 to M.I.R.-F., PGC2018-102192-B-I00 to S.O. and RTI2018-101032-J-I00 to F.F.), the CaixaImpulse 2015 Programme, the Spain EIT Health (Proof of concept 2016), the European Regional Development Fund (ERDF),the Xunta de Galicia (GRC2014/011 and ED431C2018-21), the Fundació Bosch i Gimpera, Universitat de Barcelona (F2I grant), the Generalitat de Catalunya (2017 SGR 106, 2017 SGR 124 and 2017 SGR 1707), the Fundacion Fuentes Dutor ́ , the European Research Council (ERC-2015- StG-679001- NetMoDEzyme to S.O.), and the European Community (MSCA-IF-2014-EF-661160-MetAccembly to F.F.). S.C. and E.P. acknowledge PhD fellowships from the Universitat de Barcelona (APIF grants). E.V. and R.L. thank the Institute of Biomedicine of the University of Barcelona (IBUB) and the Spanish Ministerio de Educacion, Cultura y Deporte ́ (FPU grant), respectively, for PhD grants. Partial support was provided by NIH-NIEHS River Award R35 ES03443, NIHNIEHS Superfund Program P42 ES004699, NINDS R01 DK107767, and NIDDK R01 DK103616. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. We thank Daniel Closa (IIBB−CSIC, Barcelona, Spain) for advice regarding the histological analyses.

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 compromises 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 oxa-analogs 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.

Alzheimer&rsquo, s disease (AD) is the leading cause of dementia. Non-competitive N-Methyl-D-aspartate (NMDA) receptor antagonist memantine improved cognition and molecular alterations after preclinical treatment. Nevertheless, clinical results are discouraging. In vivo efficacy of the RL-208, a new NMDA receptor blocker described recently, with favourable pharmacokinetic properties was evaluated in Senescence accelerated mice prone 8 (SAMP8), a mice model of late-onset AD (LOAD). Oral administration of RL-208 improved cognitive performance assessed by using the three chamber test (TCT), novel object recognition test (NORT), and object location test (OLT). Consistent with behavioural results, RL-208 treated-mice groups significantly changed NMDAR2B phosphorylation state levels but not NMDAR2A. Calpain-1 and Caspase-3 activity was reduced, whereas B-cell lymphoma-2 (BCL-2) levels increased, indicating reduced apoptosis in RL-208 treated SAMP8. Superoxide Dismutase 1 (SOD1) and Glutathione Peroxidase 1 (GPX1), as well as a reduction of hydrogen peroxide (H2O2), was also determined in RL-208 mice. RL-208 treatment induced an increase in mature brain-derived neurotrophic factor (mBDNF), prevented Tropomyosin-related kinase B full-length (TrkB-FL) cleavage, increased protein levels of Synaptophysin (SYN) and Postsynaptic density protein 95 (PSD95). In whole, these results point out to an improvement in synaptic plasticity. Remarkably, RL-208 also decreased the protein levels of Cyclin-Dependent Kinase 5 (CDK5), as well as p25/p35 ratio, indicating a reduction in kinase activity of CDK5/p25 complex. Consequently, lower levels of hyperphosphorylated Tau (p-Tau) were found. In sum, these results demonstrate the neuroprotectant role of RL-208 through NMDAR blockade.

This work reports the synthesis, and pharmacological and electrophysiological evaluation of new N-methyl-D-aspartic acid receptor (NMDAR) channel blocking antagonists featuring polycyclic scaffolds. Changes in the chemical structure modulate the potency and voltage dependence of inhibition. Two of the new antagonists display properties comparable to those of memantine, a clinically approved NMDAR antagonist.

Recent findings suggest that treatment with 11β-HSD1 inhibitors provides a novel approach to deal with age-related cognitive dysfunctions, including Alzheimer's disease. In this work we report potent 11β-HSD1 inhibitors featuring unexplored pyrrolidine-based polycyclic substituents. A selected candidate administered to 12-month-old SAMP8 mice for four weeks prevented memory deficits and displayed a neuroprotective action. This is the first time that 11β-HSD1 inhibitors have been studied in this broadly-used mouse model of accelerated senescence and late-onset Alzheimer's disease.

The inhibition of the enzyme soluble epoxide hydrolase (sEH) has demonstrated clinical therapeutic effects in several peripheral inflammatory-related diseases, with two compounds that have entered 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). Of interest, we have found that sEH is upregulated in brains from AD patients. We have evaluated the cognitive impairment and the pathological hallmarks in two models of age-related cognitive decline and AD using three structurally different and potent sEH inhibitors as chemical probes. Our findings supported our expectations on the beneficial effects of central sEH inhibition, regarding of reducing cognitive impairment, tau hyperphosphorylation pathology and the number of amyloid plaques. Interestingly, our results suggest that reduction of inflammation in the brain is a relevant therapeutic strategy for all stages of AD.

We recently found that a cyclohexanecarboxamide derived from 4-azatetracyclo[5.3.2.02,6.08,10]dodec-11-ene displayed low nanomolar inhibition of 11β-HSD1. In continuation of our efforts to discover potent and selective 11β-HSD1 inhibitors, herein we explored several replacements for the cyclohexane ring. Some derivatives exhibited potent inhibitory activity against human 11β-HSD1, although with low selectivity over the isoenzyme 11β-HSD2, and poor microsomal stability.

Elevated glucocorticoid (GC) exposure is widely accepted as a key factor in the age-related cognitive decline in rodents and humans. 11β-HSD1 is a key enzyme in the GCs pathway, catalyzing the conversion of 11β-dehydrocorticosterone to corticosterone in mice, with possible implications in neurodegenerative processes and cognitive impairment. Here, we determined the effect of a new 11β-HSD1 inhibitor, RL-118, administered to 12-month-old senescence-accelerated mouse-prone 8 (SAMP8) mice with neuropathological AD-like hallmarks and widely used as a rodent model of cognitive dysfunction. Behavioral tests (open field and object location) and neurodegeneration molecular markers were studied. After RL-118 treatment, increased locomotor activity and cognitive performance were found. Likewise, we found changes in hippocampal autophagy markers such as Beclin1, LC3B, AMPKα, and mTOR, indicating a progression in the autophagy process. In line with autophagy increase, a diminution in phosphorylated tau species (Ser 396 and Ser 404) jointly with an increase in ADAM10 and sAPPα indicated that an improvement in removing the abnormal proteins by autophagy might be implicated in the neuroprotective role of the 11β-HSD1 inhibitor. In addition, gene expression of oxidative stress (OS) and inflammatory markers, such as Hmox1, Aldh2, Il-1β, and Ccl3, were reduced in old treated mice in comparison to that of the control group. Consistent with this, we further demonstrate a significant correlation with autophagy markers and cognitive improvement and significant inverse correlation with autophagy, OS, and neuroinflammation markers. We concluded that inhibition of 11β-HSD1 by RL-118 prevented neurodegenerative processes and cognitive decline, acting on autophagy process, being an additional neuroprotective mechanism not described previously.

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.

The synthesis of several [4,4,3], [4,3,3], and [3,3,3]azapropellanes is reported. Several of the novel amines displayed low-micromolar activities against an amantadine-resistant H1N1 strain, but they did not show activity against an amantadine-sensitive H3N2 strain. None of the tested compounds inhibit the influenza A/M2 proton channel function. Most of the compounds did not show cytotoxicity for MDCK cells.

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.

Cinacalcet hydrochloride is the only approved drug acting as calcimimetic, a new class of compounds used in the therapy of secondary hyperparathyroidism and parathyroid carcinoma. Several generic drug manufacturers and research groups from academia have reported alternative approaches to this molecule, mainly from (R)-(+)-1-(1-naphthyl)ethylamine. There are mainly three strategies that have been used to couple this readily accessible enantiopure amine to the other part of the molecule: amide formation followed by reduction, reaction with an aldehyde and reduction of the resulting imine, and nucleophilic substitution with a suitable partner that carries a leaving group. More exotic approaches have also been disclosed. In the present review all of them are discussed. 1 Introduction 2 Synthetic Approaches Involving the Synthesis of an Amide Followed by Its Reduction 2.1 Approaches Involving Saturated Amide 2 from Acid 3 2.2 Approaches Involving Acrylamide 5 2.3 Alternatives Approaches Involving Amides 3 Synthetic Approaches Involving a Reductive Amination 3.1 Processes for the Synthesis of 3-(Trifluoromethyl)cinnamaldehyde (18) and 3-[3-(Trifluoromethyl)phenyl]propanal (20) 3.2 Processes Involving 18 3.3 Processes Involving 20 4 Synthetic Approaches Involving a Substitution Reaction 4.1 Substitutions Involving Alkyl Halides or Pseudohalides 4.2 Substitutions Involving Allyl Halides or Pseudohalides 4.3 Substitution Involving a Propynyl Mesylate 4.4 Direct Substitution without Activating the Hydroxyl Group 5 Miscellaneous Synthetic Approaches 6 Conclusions

Cinacalcet hydrochloride is the only approved drug acting as calcimimetic, a new class of compounds used in the therapy of secondary hyperparathyroidism and parathyroid carcinoma. Several generic drug manufacturers and research groups from academia have reported alternative approaches to this molecule, mainly from (R)-(+)-1-(1-naphthyl)ethylamine. There are mainly three strategies that have been used to couple this readily accessible enantiopure amine to the other part of the molecule: amide formation followed by reduction, reaction with an aldehyde and reduction of the resulting imine, and nucleophilic substitution with a suitable partner that carries a leaving group. More exotic approaches have also been disclosed. In the present review all of them are discussed. 1 Introduction 2 Synthetic Approaches Involving the Synthesis of an Amide Followed by Its Reduction 2.1 Approaches Involving Saturated Amide 2 from Acid 3 2.2 Approaches Involving Acrylamide 5 2.3 Alternatives Approaches Involving Amides 3 Synthetic Approaches Involving a Reductive Amination 3.1 Processes for the Synthesis of 3-(Trifluoromethyl)cinnamaldehyde (18) and 3-[3-(Trifluoromethyl)phenyl]propanal (20) 3.2 Processes Involving 18 3.3 Processes Involving 20 4 Synthetic Approaches Involving a Substitution Reaction 4.1 Substitutions Involving Alkyl Halides or Pseudohalides 4.2 Substitutions Involving Allyl Halides or Pseudohalides 4.3 Substitution Involving a Propynyl Mesylate 4.4 Direct Substitution without Activating the Hydroxyl Group 5 Miscellaneous Synthetic Approaches 6 Conclusions

Fibroblast growth factor 21 (FGF21), a peptide hormone with pleiotropic effects on carbohydrate and lipid metabolism, is considered a target for the treatment of diabetes. We investigated the role of peroxisome proliferator-activated receptor (PPAR) b/d deficiency in hepatic FGF21 regulation. Increased Fgf21 expression was observed in the livers of PPARb/d-null mice and in mouse primary hepatocytes when this receptor was knocked down by small interfering RNA (siRNA). Increased Fgf21 was associated with enhanced protein levels in the heme-regulated eukaryotic translation initiation factor 2a (eIF2a) kinase (HRI). This increase caused enhanced levels of phosphorylated eIF2a and activating transcription factor (ATF) 4, which is essential for Fgf21-induced expression. siRNA analysis demonstrated that HRI regulates Fgf21 expression in primary hepatocytes. Enhanced Fgf21 expression attenuated tunicamycin-induced endoplasmic reticulum stress, as demonstrated by using a neutralizing antibody against FGF21. Of note, increased Fgf21 expression in mice fed a high-fat diet or hepatocytes exposed to palmitate was accompanied by reduced PPARb/d and activation of the HRI-eIF2α-ATF4 pathway. Moreover, pharmacological activation of HRI increased Fgf21 expression and reduced lipid-induced hepatic steatosis and glucose intolerance, but these effects were not observed in Fgf21-null mice. Overall, these findings suggest that HRI is a potential target for regulating hepatic FGF21 levels., This study was partly supported by funds from the Spanish Ministry of the Economy and Competitiveness (SAF2015-65267-R to Á.M.V., SAF2014-55725 to F.V., and SAF2012-30708 and SAF2015-64146-R to M.V.-C.) and the European Union European Regional Development Fund. CIBERDEM and CIBEROBN are Instituto de Salud Carlos III Health Institute projects. T.Q.-L. is supported by a CONACyT (National Council for Science and Technology in Mexico) PhD scholarship. W.W. is supported by start-up grants from the Lee Kong Chian School of Medicine, Nanyang Technological University, and by the Région Midi-Pyrénées, France.

The M2 proton channel of influenza A virus is an integral membrane protein involved in the acidification of the viral interior, a step necessary for the release of the viral genetic material and replication of new virions. The aim of this study is to explore the mechanism of drug (un)binding to the M2 channel in order to gain insight into the structural and energetic features relevant for the development of novel inhibitors. To this end, we have investigated the binding of amantadine (Amt) to the wild type (wt) M2 channel and its V27A variant using multiple independent molecular dynamics simulations, exploratory conventional metadynamics, and multiple-walkers well-tempered metadynamics calculations. The results allow us to propose a sequential mechanism for the (un)binding of Amt to the wt M2 channel, which involves the adoption of a transiently populated intermediate (up state) leading to the thermodynamically favored down binding mode in the channel pore. Furthermore, they suggest that chloride anions play a relevant role in stabilizing the down binding mode of Amt to the wt channel, giving rise to a kinetic trapping that explains the experimentally observed pseudoirreversible inhibition of the wt channel by Amt. We propose that this trapping mechanism underlies the inhibitory activity of potent M2 channel blockers, as supported by the experimental confirmation of the irreversible binding of a pyrrolidine analogue from electrophysiological current assays. Finally, the results reveal that the thermodynamics and kinetics of Amt (un)binding is very sensitive to the V27A mutation, providing a quantitative rationale to the drastic decrease in inhibitory potency against the V27A variant. Overall, these findings pave the way to explore the inhibitory activity of Amt-related analogues in mutated M2 channel variants, providing guidelines for the design of novel inhibitors against resistant virus strains.

The adamantane scaffold is found in several marketed drugs and in many investigational 11β-HSD1 inhibitors. Interestingly, all the clinically approved adamantane derivatives are C-1 substituted. We demonstrate that, in a series of paired adamantane isomers, substitution of the adamantane in C-2 is preferred over the substitution at C-1 and is necessary for potency at human 11β-HSD1. Furthermore, the introduction of an oxygen atom in the hydrocarbon scaffold of adamantane is deleterious to 11β-HSD1 inhibition. Molecular modeling studies provide a basis to rationalize these features.

Graphical abstract, Two alternative syntheses of 2-oxaadamantan-5-amine, a novel analog of the clinically approved drug amantadine, are reported. The compound has been tested as an anti-influenza A virus agent and as an NMDA receptor antagonist. While the compound was not antivirally active, it displayed moderate activity as an NMDA receptor antagonist.