Heteroarylureas with fused bicyclic diamine cores as inhibitors of fatty acid amide hydrolase

Endocannabinoid Hydrolase Inhibitors: Potential Novel Anxiolytic Drugs

Over the past decade, the idea of targeting the endocannabinoid system to treat anxiety disorders has received increasing attention. Previous studies focused more on developing cannabinoid receptor agonists or supplementing exogenous cannabinoids, which are prone to various adverse effects due to their strong pharmacological activity and poor receptor selectivity, limiting their application in clinical research. Endocannabinoid hydrolase inhibitors are considered to be the most promising development strategies for the treatment of anxiety disorders. More recent efforts have emphasized that inhibition of two major endogenous cannabinoid hydrolases, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), indirectly activates cannabinoid receptors by increasing endogenous cannabinoid levels in the synaptic gap, circumventing receptor desensitization resulting from direct enhancement of endogenous cannabinoid signaling. In this review, we comprehensively summarize the anxiolytic effects of MAGL and FAAH inhibitors and their potential pharmacological mechanisms, highlight reported novel inhibitors or natural products, and provide an outlook on future directions in this field.

Applications of Isosteres of Piperazine in the Design of Biologically Active Compounds: Part 1

Piperazine and homopiperazine are well-studied heterocycles in drug design that have found gainful application as scaffolds and terminal elements and for enhancing the aqueous solubility of a molecule. The optimization of drug candidates that incorporate these heterocycles in an effort to refine potency, selectivity, and developability properties has stimulated the design and evaluation of a wide range of bioisosteres that can offer advantage. In this review, we summarize the design and application of bioisosteres of piperazine and homopiperazine that have almost exclusively been in the drug design arena. While there are ∼100 approved drugs that incorporate a piperazine ring, only a single marketed agricultural product is built on this heterocycle. As part of the review, we discuss some of the potential reasons underlying the relatively low level of importance of this heterocycle to the design of agrochemicals and highlight the potential opportunities for their use in contemporary research programs.

Further exploration of the structure-activity relationship of dual soluble epoxide hydrolase/fatty acid amide hydrolase inhibitors

Fatty acid amide hydrolase (FAAH) is a membrane protein that hydrolyzes endocannabinoids, and its inhibition produces analgesic and anti-inflammatory effects. The soluble epoxide hydrolase (sEH) hydrolyzes epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatetraenoic acids. EETs have anti-inflammatory and inflammation resolving properties, thus inhibition of sEH consequently reduces inflammation. Concurrent inhibition of both enzymes may represent a novel approach in the treatment of chronic pain. Drugs with multiple targets can provide a superior therapeutic effect and a decrease in side effects compared to ligands with single targets. Previously, microwave-assisted methodologies were employed to synthesize libraries of benzothiazole analogs from which high affinity dual inhibitors (e.g. 3, sEH IC₅₀ = 9.6 nM; FAAH IC₅₀ = 7 nM) were identified. Here, our structure-activity relationship studies revealed that the 4-phenylthiazole moiety is well tolerated by both enzymes, producing excellent inhibition potencies in the low nanomolar range (e.g. 6o, sEH IC₅₀ = 2.5 nM; FAAH IC₅₀ = 9.8 nM). Docking experiments show that the new class of dual inhibitors bind within the catalytic sites of both enzymes. Prediction of several pharmacokinetic/pharmacodynamic properties suggest that these new dual inhibitors are good candidates for further in vivo evaluation. Finally, dual inhibitor 3 was tested in the Formalin Test, a rat model of acute inflammatory pain. The data indicate that 3 produces antinociception against the inflammatory phase of the Formalin Test in vivo and is metabolically stable following intraperitoneal administration in male rats. Further, antinociception produced by 3 is comparable to that of ketoprofen, a traditional nonsteroidal anti-inflammatory drug. The results presented here will help toward the long-term goal of developing novel non-opioid therapeutics for pain management.

Identification of new target proteins of a Urotensin-II receptor antagonist using transcriptome-based drug repositioning approach

Drug repositioning research using transcriptome data has recently attracted attention. In this study, we attempted to identify new target proteins of the urotensin-II receptor antagonist, KR-37524 (4-(3-bromo-4-(piperidin-4-yloxy)benzyl)-N-(3-(dimethylamino)phenyl)piperazine-1-carboxamide dihydrochloride), using a transcriptome-based drug repositioning approach. To do this, we obtained KR-37524-induced gene expression profile changes in four cell lines (A375, A549, MCF7, and PC3), and compared them with the approved drug-induced gene expression profile changes available in the LINCS L1000 database to identify approved drugs with similar gene expression profile changes. Here, the similarity between the two gene expression profile changes was calculated using the connectivity score. We then selected proteins that are known targets of the top three approved drugs with the highest connectivity score in each cell line (12 drugs in total) as potential targets of KR-37524. Seven potential target proteins were experimentally confirmed using an in vitro binding assay. Through this analysis, we identified that neurologically regulated serotonin transporter proteins are new target proteins of KR-37524. These results indicate that the transcriptome-based drug repositioning approach can be used to identify new target proteins of a given compound, and we provide a standalone software developed in this study that will serve as a useful tool for drug repositioning.