1-(3-biaryloxy-2-oxopropyl)indole-5-carboxylic acids and related compounds as dual inhibitors of human cytosolic phospholipase A2α and fatty acid amide hydrolase

Cytosolic phospholipase A2α (cPLA2α) and fatty acid amide hydrolase (FAAH) are enzymes that have emerged as attractive targets for the development of analgesic and anti-inflammatory drugs. We recently reported that 1-[3-(4-octylphenoxy)-2-oxopropyl]indole-5-carboxylic acid (5) is a dual inhibitor of cPLA2α and FAAH. Structure-activity relationship studies revealed that substituents at the indole 3- and 5-positions and replacement of the indole scaffold of this compound by other heterocycles strongly influences the inhibitory potency against cPLA2α and FAAH, respectively. Herein we report the effect of variation of the 4-octyl residue of 5 and an exchange of its carboxylic acid moiety by some bioisosteric functional groups. Several of the compounds assayed were favorably active against both enzymes, and could therefore represent agents with improved analgesic and anti-inflammatory qualities in comparison with selective cPLA2 α and FAAH inhibitors.     

Design and synthesis of aryl ether inhibitors of the Bacillus anthracis enoyl-ACP reductase

The problem of increasing bacterial resistance to the current generation of antibiotics is well documented. Known resistant pathogens such as methicillin-resistant Staphylococcus aureus are becoming more prevalent, while the potential exists for developing drug-resistant pathogens for use as bioweapons, such as Bacillus anthracis. The biphenyl ether antibacterial agent, triclosan, exhibits broad-spectrum activity by targeting the fatty acid biosynthetic pathway through inhibition of enoyl-acyl carrier protein reductase (ENR) and provides a potential scaffold for the development of new, broad-spectrum antibiotics. We used a structure-based approach to develop novel aryl ether analogues of triclosan that target ENR, the product of the fabI gene, from B. anthracis (BaENR). Structure-based design methods were used for the expansion of the compound series including X-ray crystal structure determination, molecular docking, and QSAR methods. Structural modifications were made to both phenyl rings of the 2-phenoxyphenyl core. A number of compounds exhibited improved potency against BaENR and increased efficacy against both the Sterne strain of B. anthracis and the methicillin-resistant strain of S. aureus. X-ray crystal structures of BaENR in complex with triclosan and two other compounds help explain the improved efficacy of the new compounds and suggest future rounds of optimization that might be used to improve their potency.     

Position and Length of Fatty Acids Strongly Affect Receptor Selectivity Pattern of Human Pancreatic Polypeptide Analogues

Pancreatic polypeptide (PP) is a satiety‐inducing gut hormone targeting predominantly the Y₄ receptor within the neuropeptide Y multiligand/multireceptor family. Palmitoylated PP‐based ligands have already been reported to exert prolonged satiety‐inducing effects in animal models. Here, we suggest that other lipidation sites and different fatty acid chain lengths may affect receptor selectivity and metabolic stability. Activity tests revealed significantly enhanced potency of long fatty acid conjugates on all four Y receptors with a preference of position 22 over 30 at Y₁, Y₂ and Y₅ receptors. Improved Y receptor selectivity was observed for two short fatty acid analogues. Moreover, [K³⁰(E‐Prop)]hPP_2?36 ( 15 ) displayed enhanced stability in blood plasma and liver homogenates. Thus, short chain lipidation of hPP at key residue 30 is a promising approach for anti‐obesity therapy because of maintained selectivity and a sixfold increased plasma half‐life.     

Structure-activity relationships and mechanism of action of Eph-ephrin antagonists: interaction of cholanic acid with the EphA2 receptor

The Eph-ephrin system, including the EphA2 receptor and the ephrinA1 ligand, plays a critical role in tumor and vascular functions during carcinogenesis. We previously identified (3α,5β)-3-hydroxycholan-24-oic acid (lithocholic acid) as an Eph-ephrin antagonist that is able to inhibit EphA2 receptor activation; it is therefore potentially useful as a novel EphA2 receptor-targeting agent. Herein we explore the structure-activity relationships of a focused set of lithocholic acid derivatives based on molecular modeling investigations and displacement binding assays. Our exploration shows that while the 3-α-hydroxy group of lithocholic acid has a negligible role in recognition of the EphA2 receptor, its carboxylate group is critical for disrupting the binding of ephrinA1 to EphA2. As a result of our investigation, we identified (5β)-cholan-24-oic acid (cholanic acid) as a novel compound that competitively inhibits the EphA2-ephrinA1 interaction with higher potency than lithocholic acid. Surface plasmon resonance analysis indicates that cholanic acid binds specifically and reversibly to the ligand binding domain of EphA2, with a steady-state dissociation constant (K(D) ) in the low micromolar range. Furthermore, cholanic acid blocks the phosphorylation of EphA2 as well as cell retraction and rounding in PC3 prostate cancer cells, two effects that depend on EphA2 activation by the ephrinA1 ligand. These findings suggest that cholanic acid can be used as a template structure for the design of effective EphA2 antagonists, and may have potential impact in the elucidation of the role played by this receptor in pathological conditions.     

Development of Benzophenone‐Alkyne Bifunctional Sigma Receptor Ligands

Sigma (σ) receptors are unique non‐opioid binding sites that are associated with a broad range of disease states. Sigma‐2 receptors provide a promising target for diagnostic imaging and pharmacological interventions to curb tumor progression. Most recently, the progesterone receptor (PGRMC1, 25 kDa) has been shown to have σ2 receptor‐like binding properties, thus highlighting the need to understand the biological function of an 18 kDa protein that exhibits σ2‐like photoaffinity labeling (denoted here as σ2‐18k) but the amino acid sequence of which is not known. In order to provide new tools for the study of the σ2‐18k protein, we have developed bifunctional σ receptor ligands each bearing a benzophenone photo‐crosslinking moiety and an alkyne group to which an azide‐containing biotin affinity tag can be covalently attached through click chemistry after photo‐crosslinking. Although several compounds showed favorable σ2 binding properties, the highest affinity (2 nM ) and the greatest potency in blocking photolabeling of σ2‐18k by a radioactive photoaffinity ligand was shown by compound 22 . These benzophenone‐alkyne σ receptor ligands might therefore be amenable for studying the σ2‐18k protein through chemical biology approaches. To the best of our knowledge, these compounds represent the first reported benzophenone‐containing clickable σ receptor ligands, which might potentially have broad applications based on the “plugging in” of various tags.     

Three New Fatty Acid Esters from the Mushroom Boletus pseudocalopus

A bioassay-guided fractionation and chemical investigation of a MeOH extract of the Korean wild mushroom Boletus pseudocalopus resulted in the identification of three new fatty acid esters, named calopusins A-C (1-3), along with two known fatty acid methyl esters (4-5). These new compounds are structurally unique fatty acid esters with a 2,3-butanediol moiety. Their structures were elucidated through 1D- and 2D-NMR spectroscopic data and GC-MS analysis as well as a modified Mosher's method. The new compounds 1-3 showed significant inhibitory activity against the proliferation of the tested cancer cell lines with IC(50) values in the range 2.77-12.51 μM.     

2‐Aminothiazoles with Improved Pharmacotherapeutic Properties for Treatment of Prion Disease

Recently, we described the aminothiazole lead (4‐biphenyl‐4‐ylthiazol‐2‐yl)‐(6‐methylpyridin‐2‐yl)‐amine ( 1 ), which exhibits many desirable properties, including excellent stability in liver microsomes, oral bioavailability of ～40 %, and high exposure in the brains of mice. Despite its good pharmacokinetic properties, compound 1 exhibited only modest potency in mouse neuroblastoma cells overexpressing the disease‐causing prion protein PrP^Sc. Accordingly, we sought to identify analogues of 1 with improved antiprion potency in ScN2a‐cl3 cells while retaining similar or superior properties. Herein we report the discovery of improved lead compounds such as (6‐methylpyridin‐2‐yl)‐[4‐(4‐pyridin‐3‐yl‐phenyl)thiazol‐2‐yl]amine and cyclopropanecarboxylic acid (4‐biphenylthiazol‐2‐yl)amide, which exhibit brain exposure/EC₅₀ ratios at least tenfold greater than that of compound 1 .     

Improvement of corrosion protection of steel by incorporation of a new phosphonated fatty acid in a phosphorus-containing polymer coating obtained by UV curing

Six formulations containing diacrylate monomers (from 89 to 92.5% (w/w)) as well as a phosphonated methacrylate monomer (from 1 to 10% (w/w)) were prepared. All formulations were UV-cured and the corrosion performance of the resulting coatings applied onto a steel substrate was assessed by electrochemical impedance spectroscopy (EIS). It was first shown that the coatings containing phosphonic acid methacrylate (MAPC1(OH)₂) instead of methacrylate phosphonic dimethyl ester (MAPC1) presented higher corrosion protection related to the strong adhesive properties of phosphonic acid on the metal substrate. A minimum MAPC1(OH)₂ content of 2.5% was determined to provide the highest impedance values (best efficiency). Then, a new bio-based compound, i.e. phosphonic acid-bearing oleic acid (phosphonated fatty acid), was synthesized and added as an inhibitor to the formulations. In the presence of this compound, the corrosion protection was notably improved. The beneficial effect of phosphonated fatty acid was explained by its inhibitive action at the steel/coating interface and by the improvement of the barrier properties.     

Proteomics of Mouse Heart Ventricles Reveals Mitochondria and Metabolism as Major Targets of a Post-Infarction Short-Acting GLP1Ra-Therapy

Cardiovascular disease is the main cause of death worldwide, making it crucial to search for new therapies to mitigate major adverse cardiac events (MACEs) after a cardiac ischemic episode. Drugs in the class of the glucagon-like peptide-1 receptor agonists (GLP1Ra) have demonstrated benefits for heart function and reduced the incidence of MACE in patients with diabetes. Previously, we demonstrated that a short-acting GLP1Ra known as DMB (2-quinoxalinamine, 6,7-dichloro-N-[1,1-dimethylethyl]-3-[methylsulfonyl]-,6,7-dichloro-2-methylsulfonyl-3-N-tert-butylaminoquinoxaline or compound 2, Sigma) also mitigates adverse postinfarction left ventricular remodeling and cardiac dysfunction in lean mice through activation of parkin-mediated mitophagy following infarction. Here, we combined proteomics with in silico analysis to characterize the range of effects of DMB in vivo throughout the course of early postinfarction remodeling. We demonstrate that the mitochondrion is a key target of DMB and mitochondrial respiration, oxidative phosphorylation and metabolic processes such as glycolysis and fatty acid beta-oxidation are the main biological processes being regulated by this compound in the heart. Moreover, the overexpression of proteins with hub properties identified by protein–protein interaction networks, such as Atp2a2, may also be important to the mechanism of action of DMB. Data are available via ProteomeXchange with identifier PXD027867.     

New Pyridone-Based Derivatives as Cannabinoid Receptor Type 2 Agonists

The activation of the human cannabinoid receptor type II (CB2R) is known to mediate analgesic and anti-inflammatory processes without the central adverse effects related to cannabinoid receptor type I (CB1R). In this work we describe the synthesis and evaluation of a novel series of N-aryl-2-pyridone-3-carboxamide derivatives tested as human cannabinoid receptor type II (CB2R) agonists. Different cycloalkanes linked to the N-aryl pyridone by an amide group displayed CB2R agonist activity as determined by intracellular [cAMP] levels. The most promising compound 8d exhibited a non-toxic profile and similar potency (EC50 = 112 nM) to endogenous agonists Anandamide (AEA) and 2-Arachidonoylglycerol (2-AG) providing new information for the development of small molecules activating CB2R. Molecular docking studies showed a binding pose consistent with two structurally different agonists WIN-55212-2 and AM12033 and suggested structural requirements on the pyridone substituents that can satisfy the orthosteric pocket and induce an agonist response. Our results provide additional evidence to support the 2-pyridone ring as a suitable scaffold for the design of CB2R agonists and represent a starting point for further optimization and development of novel compounds for the treatment of pain and inflammation.     

New phospholipid fatty acids from the marine spongeCinachyrella alloclada uliczka

The fatty acid composition of phospholipids from the Senegalese spongeCinachyrella alloclada was examined. Two new fatty acids not hitherto found in nature, namely 10,13-octadecadienoic acid and 16-tricosenoic acid, were identified. 8-Hexadecenoic, 13-nonadecenoic and 5,9,13-trimethyltretradecanoic fatty acids were also found for the first time in sponges. The latter compound (1.4% of the total fatty acid mixture), an isoprenoid fatty acid, accompanies the major fatty acid 4,8,12-trimethyltridecanoic acid (19.7%). The monomethyl branched fatty acids (22%) identified include 23-methylpentacosanoic acid (anteiso-26∶0), not previously observed in sponged. The major long-chain fatty acids encountered were the known 17-tetracosenoic 19-heptacosadienoic and 5,9,23-tricontatrienoic acid. Some sixty fatty acids were identified as methyl esters andN-acyl pyrrolidides by gas chromatography and gas chromatography/mass spectrometry.     

Old molecules for new receptors: Trp(Nps) dipeptide derivatives as vanilloid TRPV1 channel blockers

The transient receptor potential vanilloid member 1 (TRPV1), an integrator of multiple pain-producing stimuli, is regarded nowadays as an important biological target for the discovery of novel analgesics. Here, we describe the first experimental evidence for the behavior of an old family of analgesic dipeptides, namely Xaa-Trp(Nps) and Trp(Nps)-Xaa (Xaa=Lys, Arg) derivatives, as potent TRPV1 channel blockers. We also report the synthesis and biological investigation of a series of new conformationally restricted Trp(Nps)-dipeptide derivatives with improved TRPV1/NMDA selectivity. Compound 15 b, which incorporates an N-terminal 2S-azetidine-derived Arg residue, was the most selective compound in this series. Collectively, a new family of TRPV1 channel blockers emerged from our results, although further modifications are required to fine-tune the potency/selectivity/toxicity balance.     

Volatile compounds of oxidized pork phospholipids

Volatile compounds from oxidized pork muscle phospholipids (PL) were analyzed by a purge-and-trap method. Total volatile compounds were highly correlated with thiobarbituric acid-reactive substances, mainly as a consequence of alkanals. Major compounds of the 32 identified substances were alkanals (6023 ng nonane equivalents/mg PL), followed by 2-alkenals (514 ng nonane eq/mg PL) and 2,4-alkadienals (368 ng nonane eq/mg PL). Hexanal (4850 ng nonane eq/mg PL) was the major compound from the oxidation of n-6 fatty acids (mainly linoleic and arachidonic acid). Volatile compounds from the oxidation of n-3 fatty acids were only minor and included 2,4-heptadienal (45 ng nonane eq/mg PL) and 2-pentenal and 2-hexenal (49 ng nonane eq/mg PL). Finally, nonanal, a degradation compound from oleic acid, was present at a low level (200 ng nonane eq/mg PL) and remained constant during oxidation, which confirmed that monounsaturated fatty acids were stable toward metal-catalyzed oxidation. With the exception of ester compounds, identified volatiles were qualitatively similar to those obtained in simpler systems, such as fatty acids or vegetable oils. Quantitatively, the volatile compound composition reflected the fatty acid composition of PL.     

Monoacylglycerols Activate Capsaicin Receptor, TRPV1

Transient receptor potential vanilloid subtype 1 (TRPV1) is known as capsaicin (CAP) receptor and activated by CAP. Activation of TRPV1 by CAP increases energy expenditure and thermogenesis in rodents or human. Therefore, TRPV1 may be target for energy expenditure enhancement and thermogenesis. To search for novel TRPV1 agonist, we screened 19 types of foods by using TRPV1-expressing HEK293 cells. TRPV1 was activated by hexane extract of wheat flour, and its functional compounds were 1-monoacylglycerols containing oleic, linoleic, and alpha-linolenic acids. Their potencies (EC50) were about 50 times larger than that of CAP and their efficacies (maximal response) were about half of that of CAP. TRPV1 was activated by 1-monoacylglycerols (MGs) having C18 and C20 unsaturated and C8-C12 saturated fatty acid (FA). Moreover, 2-MGs having C18 and C20 unsaturated FA acted on TRPV1 with the same potency. On the other hand, no activation of TRPV1 was induced by MGs having C16 and C18 saturated FA, di- or triacylglycerols of C18:1 FA. Pain-relating aversive responses were induced when TRPV1-activating 1-monoacylglycerols (50 mM) was administered subcutaneously into rat hind paw. These effects were inhibited by the co-injection of capsazepine (10 mM) which is a TRPV1 competitive antagonist. These results suggested that these 1-monoacylglycerols activate TRPV1 in vitro and in vivo.     

Designing Multitarget Anti-inflammatory Agents: Chemical Modulation of the Lumiracoxib Structure toward Dual Thromboxane Antagonists-COX-2 Inhibitors

A series of lumiracoxib derivatives were designed to explore the influence of isosteric substitution on balancing COX-2 inhibition and thromboxane A(2) prostanoid (TP) receptor antagonism. The compounds were synthesized through a copper-catalyzed coupling procedure and characterized for their pK(a) values. TP receptor antagonism was assessed on human platelets; COX-2 inhibition was determined on human isolated monocytes and human whole blood. TPα receptor binding of the most promising compounds was evaluated through radioligand binding assays. Some of the isosteric substitutions at the carboxylic acid group afforded compounds with improved TP receptor antagonism; of these, a tetrazole derivative retained good COX-2 inhibitory activity and selectivity. The identification of this tetrazole acting as a balanced dual-acting compound in human whole blood, along with SAR analysis of the synthesized lumiracoxib derivatives, might contribute to the rational design of a new class of cardioprotective anti-inflammatory agents.     

Identification of an amido-amine component in diethanolamide

Diethanolamide products made by the con-densation of diethanolamine and fatty acid are known to contain, in addition to the amide, ex-cess diethanolamine, fatty acid soap of diethano-lamine and water. In a recent examination of some amide products, a new amido-amine com-pound was isolated and identified. This com-pound is formed from two moles of diethano-lamine and one mole of fatty acid and is present at levels as high as 10% of amide product. The amido-amine was isolated by extraction with isobutanol from an acidic solution of the amide. The structure of this new compound was verified by its chemical reactivity and by in-strumental analyses. Methods of synthesis were also studied. Presented at the AOCS Meeting in New Orleans, May 1967     

Development of Novel Inhibitors for Histone Methyltransferase SET7/9 based on Cyproheptadine

The histone methyltransferase SET7/9 methylates not only histone but also non‐histone proteins as substrates, and therefore, SET7/9 inhibitors are considered candidates for the treatment of diseases. Previously, our group identified cyproheptadine, used clinically as a serotonin receptor antagonist and histamine receptor (H1) antagonist, as a novel scaffold of the SET7/9 inhibitor. In this work, we focused on dibenzosuberene as a substructure of cyproheptadine and synthesized derivatives with various functional groups. Among them, the compound bearing a 2‐hydroxy group showed the most potent activity. On the other hand, a 3‐hydroxy group or another hydrophilic functional group such as acetamide decreased the activity. Structural analysis clarified a rationale for the improved potency only by tightly restricted location and type of the hydrophilic group. In addition, a SET7/9 loop, which was only partially visible in the complex with cyproheptadine, became more clearly visible in the complex with 2‐hydroxycyproheptadine. These results are expected to be helpful for further structure‐based development of SET7/9 inhibitors.     

9‐Oxo‐10(E),12(Z),15(Z)‐Octadecatrienoic Acid Activates Peroxisome Proliferator‐Activated Receptor α in Hepatocytes

The peroxisome proliferator‐activated receptor (PPAR)α is mainly expressed in the liver and plays an important role in the regulation of lipid metabolism. It has been reported that PPARα activation enhances fatty acid oxidation and reduces fat storage. Therefore, PPARα agonists are used to treat dyslipidemia. In the present study, we found that 9‐oxo‐10(E),12(Z),15(Z)‐octadecatrienoic acid (9‐oxo‐OTA), which is a α‐linolenic acid (ALA) derivative, is present in tomato (Solanum lycopersicum) extract. We showed that 9‐oxo‐OTA activated PPARα and induced the mRNA expression of PPARα target genes in murine primary hepatocytes. These effects promoted fatty acid uptake and the secretion of β‐hydroxybutyrate, which is one of the endogenous ketone bodies. We also demonstrated that these effects of 9‐oxo‐OTA were not observed in PPARα‐knockout (KO) primary hepatocytes. To our knowledge, this is the first study to report that 9‐oxo‐OTA promotes fatty acid metabolism via PPARα activation and discuss its potential as a valuable food‐derived compound for use in the management of dyslipidemia.     

Modulation on C‐ and N‐Terminal Moieties of a Series of Potent and Selective Linear Tachykinin NK2 Receptor Antagonists

Herein we describe the synthesis of a series of new potent tachykinin NK₂ receptor antagonists by the modulation of the C‐ and N‐terminal moieties of ibodutant (MEN 15596, 1 ). The N‐terminal benzo[b]thiophene ring was replaced by different substituted naphthalenes and benzofurans, while further modifications were evaluated at the C‐terminal tetrahydropyran moiety. Most compounds demonstrated a high affinity for the human NK₂ receptor and high in vitro antagonist potency, indicating that a wide range of substituents at both termini can be incorporated in the molecule without detrimental effects on the interactions with the NK₂ receptor. Selected compounds were tested in vivo confirming their activity as NK₂ antagonists. In particular, after both iv and id administration to guinea pig, compound 61 b was able to antagonize NK₂‐induced colonic contractions with a potency and duration‐of‐action fully comparable to the reference compound 1 (MEN 15596, ibodutant).