5-Aminothiazoles Reveal a New Ligand-Binding Site on Prolyl Oligopeptidase Which is Important for Modulation of Its Protein-Protein Interaction-Derived Functions.

A series of novel 5-aminothiazole-based ligands for prolyl oligopeptidase (PREP) comprise selective, potent modulators of the protein-protein interaction (PPI)-mediated functions of PREP, although they are only weak inhibitors of the proteolytic activity of PREP. The disconnected structure-activity relationships are significantly more pronounced for the 5-aminothiazole-based ligands than for the earlier published 5-aminooxazole-based ligands. Furthermore, the stability of the 5-aminothiazole scaffold allowed exploration of wider substitution patterns than that was possible with the 5-aminooxazole scaffold.

A prolyl oligopeptidase inhibitor reduces tau pathology in cellular models and in mice with tauopathy.

Tauopathies are neurodegenerative diseases that are characterized by accumulation of hyperphosphorylated tau protein, higher-order aggregates, and tau filaments. Protein phosphatase 2A (PP2A) is a major tau dephosphorylating phosphatase, and a decrease in its activity has been demonstrated in tauopathies, including Alzheimer's disease. Prolyl oligopeptidase is a serine protease that is associated with neurodegeneration, and its inhibition normalizes PP2A activity without toxicity under pathological conditions.

Potent dual MAGL/FAAH inhibitor AKU-005 engages endocannabinoids to diminish meningeal nociception implicated in migraine pain.

Background: Engaging the endocannabinoid system through inhibition of monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), degrading endocannabinoids (endoCBs) 2-arachidonoylglycerol (2-AG) and anandamide (AEA), was proposed as a promising approach to ameliorate migraine pain. However, the activity of MAGL and FAAH and action of endoCB on spiking activity of meningeal afferents, from which migraine pain originates, has not been explored thus far. Therefore, we here explored the analgesic effects of endoCB enhancement in rat and human meningeal tissues.

Utilizing PET and MALDI Imaging for Discovery of a Targeted Probe for Brain Endocannabinoid /-Hydrolase Domain 6 (ABHD6).

Multimodal imaging provides rich biological information, which can be exploited to study drug activity, disease associated phenotypes, and pharmacological responses. Here we show discovery and validation of a new probe targeting the endocannabinoid α/β-hydrolase domain 6 (ABHD6) enzyme by utilizing positron emission tomography (PET) and matrix-assisted laser desorption/ionization (MALDI) imaging. [F]JZP-MA-11 as the first PET ligand for imaging of the ABHD6 is reported and specific uptake in ABHD6-rich peripheral tissues and major brain regions was demonstrated using PET.

Inhibiting Endocannabinoid Hydrolysis as Emerging Analgesic Strategy Targeting a Spectrum of Ion Channels Implicated in Migraine Pain.

Migraine is a disabling neurovascular disorder characterized by severe pain with still limited efficient treatments. Endocannabinoids, the endogenous painkillers, emerged, alternative to plant cannabis, as promising analgesics against migraine pain. In this thematic review, we discuss how inhibition of the main endocannabinoid-degrading enzymes, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), could raise the level of endocannabinoids (endoCBs) such as 2-AG and anandamide in order to alleviate migraine pain.

Metabolomics of Synovial Fluid and Infrapatellar Fat Pad in Patients with Osteoarthritis or Rheumatoid Arthritis.

Osteoarthritis (OA) and autoimmune-driven rheumatoid arthritis (RA) are inflammatory joint diseases with complex and insufficiently understood pathogeneses. Our objective was to characterize the metabolic fingerprints of synovial fluid (SF) and its adjacent infrapatellar fat pad (IFP) obtained during the same surgical operation from OA and RA knees. Non-targeted metabolite profiling was performed for 5 non-inflammatory trauma controls, 10 primary OA (pOA) patients, and 10 seropositive RA patients with high-resolution mass spectrometry-based techniques, and metabolites were matched with known metabolite identities.

Distinct Activity of Endocannabinoid-Hydrolyzing Enzymes MAGL and FAAH in Key Regions of Peripheral and Central Nervous System Implicated in Migraine.

In migraine pain, cannabis has a promising analgesic action, which, however, is associated with side psychotropic effects. To overcome these adverse effects of exogenous cannabinoids, we propose migraine pain relief via activation of the endogenous cannabinoid system (ECS) by inhibiting enzymes degrading endocannabinoids. To provide a functional platform for such purpose in the peripheral and central parts of the rat nociceptive system relevant to migraine, we measured by activity-based protein profiling (ABPP) the activity of the main endocannabinoid-hydrolases, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH).

Evaluation of FASN inhibitors by a versatile toolkit reveals differences in pharmacology between human and rodent FASN preparations and in antiproliferative efficacy in vitro vs. in situ in human cancer cells.

De novo synthesis of fatty acids is essential to maintain intensive proliferation of cancer cells. Unlike normal cells that utilize food-derived circulating lipids for their fuel, cancer cells rely on heightened lipogenesis irrespective of exogenous lipid availability. Overexpression and activity of the multidomain enzyme fatty acid synthase (FASN) is crucial in supplying palmitate for protumorigenic activity.

Regulating membrane lipid levels at the synapse by small-molecule inhibitors of monoacylglycerol lipase: new developments in therapeutic and PET imaging applications.

Monoacylglycerol lipase (MAGL) is a major endocannabinoid hydrolyzing enzyme and can be regulated to control endogenous lipid levels in the brain. This review highlights the pharmacological roles and in vivo PET imaging of MAGL in brain.

Discovery of 12-Thiazole Abietanes as Selective Inhibitors of the Human Metabolic Serine Hydrolase hABHD16A.

Screening of an in-house library of compounds identified 12-thiazole abietanes as a new class of reversible inhibitors of the human metabolic serine hydrolase. Further optimization of the first hit compound lead to the 2-methylthiazole derivative , with an IC value of 3.4 ± 0.

Design, synthesis, and biological evaluation of 2,4-dihydropyrano[2,3-c]pyrazole derivatives as autotaxin inhibitors.

Inhibition of Autotaxin (ATX) is a potential treatment strategy for several diseases, including tumors with elevated ATX-lysophosphatidic acid (LPA) signaling. Combining structure-based virtual screening together with hen egg-white Autotaxin (ewATX) activity assays enabled the discovery of novel small-molecule ATX inhibitors with a 2,4-dihydropyrano[2,3-c]pyrazole scaffold. These compounds are suggested to bind to the lipophilic pocket, leaving the active site unrestrained.

Synthesis and preclinical evaluation of [C]MA-PB-1 for in vivo imaging of brain monoacylglycerol lipase (MAGL).

MAGL is a potential therapeutic target for oncological and psychiatric diseases. Our objective was to develop a PET tracer for in vivo quantification of MAGL. We report [C]MA-PB-1 as an irreversible MAGL inhibitor PET tracer.

Chemoproteomic, biochemical and pharmacological approaches in the discovery of inhibitors targeting human α/β-hydrolase domain containing 11 (ABHD11).

ABHD11 (α/β-hydrolase domain containing 11) is a non-annotated enzyme belonging to the family of metabolic serine hydrolases (mSHs). Its natural substrates and products are unknown. Using competitive activity-based protein profiling (ABPP) to identify novel inhibitors of human (h)ABHD11, three compounds from our chemical library exhibited low nanomolar potency towards hABHD11.

In Vivo Characterization of the Ultrapotent Monoacylglycerol Lipase Inhibitor {4-[bis-(benzo[d][1,3]dioxol-5-yl)methyl]-piperidin-1-yl}(1H-1,2,4-triazol-1-yl)methanone (JJKK-048).

Monoacylglycerol lipase (MAGL) is a serine hydrolase that acts as a principal degradative enzyme for the endocannabinoid 2-arachidonoylglycerol (2-AG). In addition to terminating the signaling function of 2-AG, MAGL liberates arachidonic acid to be used as a primary source for neuroinflammatory prostaglandin synthesis in the brain. MAGL activity also contributes to cancer pathogenicity by producing precursors for tumor-promoting bioactive lipids.

A Sensitive and Versatile Fluorescent Activity Assay for ABHD12.

Despite great progress in identifying and deorphanizing members of the human metabolic serine hydrolase (mSH) family, the fundamental role of numerous enzymes in this large protein class has remained unclear. One recently found mSH is α/β-hydrolase domain containing 12 (ABHD12) enzyme, whose natural substrate in vivo appears to be the lysophospholipid lysophosphatidylserine (LPS). In vitro, ABHD12 together with monoacylglycerol lipase (MAGL) and ABHD6 hydrolyzes also monoacylglycerols (MAGs) such as the primary endocannabinoid 2-arachidonoyl glycerol (2-AG).

A Sensitive and Versatile Fluorescent Activity Assay for ABHD6.

The α/β-hydrolase domain-containing 6 (ABHD6) enzyme is a newly found serine hydrolase whose substrate profile resembles that of monoacylglycerol lipase (MAGL), the major 2-arachidonoyl glycerol (2-AG) hydrolase in the brain. Here, we describe a sensitive fluorescent assay of ABHD6 activity in a 96-well-plate format that allows parallel testing of inhibitor activities of up to 40 compounds in a single assay. The method utilizes lysates of HEK293 cells transiently overexpressing human ABHD6 as the enzymatic source, and kinetically monitors glycerol liberated in the hydrolysis of 1(3)-AG, the preferred arachidonoyl glycerol isomer.

Potent and selective N-(4-sulfamoylphenyl)thiourea-based GPR55 agonists.

To date, many known G protein-coupled receptor 55 (GPR55) ligands are those identified among the cannabinoids. In order to further study the function of GPR55, new potent and selective ligands are needed. In this study, we utilized the screening results from PubChem bioassay AID 1961 which reports the results of Image-based HTS for Selective Agonists of GPR55.

Revisiting 1,3,4-Oxadiazol-2-ones: Utilization in the Development of ABHD6 Inhibitors.

This article describes our systematic approach to exploring the utility of the 1,3,4-oxadiazol-2-one scaffold in the development of ABHD6 inhibitors. Compound 3-(3-aminobenzyl)-5-methoxy-1,3,4-oxadiazol-2(3H)-one (JZP-169, 52) was identified as a potent inhibitor of hABHD6, with an IC₅₀ value of 216 nM. This compound at 10 μM concentration did not inhibit any other endocannabinoid hydrolases, such as FAAH, MAGL and ABHD12, or bind to the cannabinoid receptors (CB₁ and CB₂).

Increased tonic cannabinoid CB1R activity and brain region-specific desensitization of CB1R Gi/o signaling axis in mice with global genetic knockout of monoacylglycerol lipase.

In mammalian brain, monoacylglycerol lipase (MAGL) is the primary enzyme responsible for terminating signaling function of the endocannabinoid 2-arachidonoylglycerol (2-AG). Previous in vivo studies with mice indicate that both genetic and chronic pharmacological inactivation of MAGL result in 8-30-fold increase of 2-AG concentration in the brain, causing desensitization and downregulation of cannabinoid CB1 receptor (CB1R) activity, leading to functional and behavioral tolerance. However, direct evidence for reduced CB1R activity in the brain is lacking.

New quinolone- and 1,8-naphthyridine-3-carboxamides as selective CB2 receptor agonists with anticancer and immuno-modulatory activity.

Several recent studies suggest that selective CB2 receptor agonists may represent a valid pharmacological approach in the treatment of various diseases due to the absence of relevant psychoactive side effect. In this study, we synthesized and tested a series of new quinoline-2(1H)-one- and 4-hydroxy-2-oxo-1,2-dihydro-1,8-naphthyridine derivatives characterized by a 4-methylcyclohexylamido substituent in position 3 of the heterocyclic nucleus with high CB2 receptor affinity and selectivity. Two compounds showing the best binding and selectivity profile behaved as a full agonist and a partial agonist at the CB2 receptor and induced a concentration-dependent decrease of cell viability on LNCaP, a prostatic cancer cell line expressing CB2 receptor.

Loratadine analogues as MAGL inhibitors.

Compound 12a (JZP-361) acted as a potent and reversible inhibitor of human recombinant MAGL (hMAGL, IC50=46 nM), and was found to have almost 150-fold higher selectivity over human recombinant fatty acid amide hydrolase (hFAAH, IC50=7.24 μM) and 35-fold higher selectivity over human α/β-hydrolase-6 (hABHD6, IC50=1.79 μM).

Optimization of 1,2,5-thiadiazole carbamates as potent and selective ABHD6 inhibitors.

At present, inhibitors of α/β-hydrolase domain 6 (ABHD6) are viewed as a promising approach to treat inflammation and metabolic disorders. This article describes the development of 1,2,5-thiadiazole carbamates as ABHD6 inhibitors. Altogether, 34 compounds were synthesized, and their inhibitory activity was tested using lysates of HEK293 cells transiently expressing human ABHD6 (hABHD6).

Synthesis, biological activity and molecular modeling of new biphenylic carboxamides as potent and selective CB2 receptor ligands.

The CB2 receptor is a therapeutic target of increasing importance for several diseases, including pain, inflammation, neurodegeneration, cancer and osteoporosis. While several compounds showing CB2-selective agonist or inverse agonist properties have been developed, only few CB2 receptor selective neutral antagonists are actually known. Such type of compounds could be useful to study more in depth the role of the CB2 receptor, because they lack the ability to counteract its "constitutive" activity.

Biochemical and pharmacological characterization of the human lymphocyte antigen B-associated transcript 5 (BAT5/ABHD16A).

Background: Human lymphocyte antigen B-associated transcript 5 (BAT5, also known as ABHD16A) is a poorly characterized 63 kDa protein belonging to the α/β-hydrolase domain (ABHD) containing family of metabolic serine hydrolases. Its natural substrates and biochemical properties are unknown.

Methodology/principal Findings: Amino acid sequence comparison between seven mammalian BAT5 orthologs revealed that the overall primary structure was highly (≥95%) conserved.