ABSTRACT
Biological studies on the endocannabinoid system (ECS) have suggested that monoacylglycerol lipase (MAGL), an essential enzyme responsible for the hydrolysis of 2-arachidonoylglycerol (2-AG), is a novel target for developing antidepressants. A decrease of 2-AG levels in the hippocampus of the brain has been observed in depressive-like models induced by chronic stress. Herein, employing a structure-based approach, we designed and synthesized a new class of (piperazine-1-carbonyl) quinolin-2(1H)-one derivatives as potent, reversible and selective MAGL inhibitors. And detailed structure-activity relationships (SAR) studies were discussed. Compound 27 (IC50 = 10.3 nM) exhibited high bioavailability (92.7%) and 2-AG elevation effect in vivo. Additionally, compound 27 exerted rapid antidepressant effects caused by chronic restraint stress (CRS) and didn't show signs of addictive properties in the conditioned place preference (CPP) assays. Our study is the first to report that reversible MAGL inhibitors can treat chronic stress-induced depression effectively, which may provide a new potential therapeutic strategy for the discovery of an original class of safe, rapid antidepressant drugs.
Subject(s)
Enzyme Inhibitors , Monoacylglycerol Lipases , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Monoacylglycerol Lipases/metabolism , Depression/drug therapy , Monoglycerides , Structure-Activity Relationship , Antidepressive Agents/pharmacology , Antidepressive Agents/therapeutic use , EndocannabinoidsABSTRACT
Most of the current monoacylglycerol lipase (MAGL) inhibitors function by an irreversible mechanism of action, causing a series of side effects. Herein, starting from irreversible inhibitors, 25 compounds were synthesized and evaluated in vitro for MAGL inhibition, among which, compound 36 showed the most potent inhibitory activity (IC50 = 15 nM). Crucially, docking studies demonstrated that the m-chlorine-substituted aniline fragment occupied a hydrophobic subpocket enclosed by side chains of Val191, Tyr194, Val270, and Lys273, which creatively identify a new key anchoring point for the development of new MAGL inhibitors. Furthermore, in vivo evaluation innovatively revealed that this reversible inhibitor 36 significantly ameliorated depressive-like behaviors induced by reserpine. To the best of our knowledge, this is the first time that reversible inhibitors of MAGL were developed to support MAGL as a potential therapeutic target for depression.
Subject(s)
Enzyme Inhibitors/chemistry , Monoacylglycerol Lipases/antagonists & inhibitors , Piperidines/chemistry , Animals , Binding Sites , Cell Line , Cell Survival/drug effects , Drug Design , Drug Evaluation, Preclinical , Enzyme Inhibitors/metabolism , Enzyme Inhibitors/pharmacology , Half-Life , Humans , Kinetics , Mice , Microsomes, Liver/metabolism , Molecular Docking Simulation , Monoacylglycerol Lipases/metabolism , Piperidines/metabolism , Piperidines/pharmacology , Protein Structure, Tertiary , Rats , Structure-Activity RelationshipABSTRACT
Due to ineffectiveness and side effects of existing analgesics, chronic pain has become one of the most complex and difficult problems in the clinic. Monoacylglycerol lipase (MAGL) is an essential hydrolase in the endocannabinoid system and has been identified as a potential target for the treatment of pain. In the present study, we designed and synthesized twelve tanshinone IIA analogs and screened their activity against MAGL. Selected compounds were tested for analgesic activity in vivo, with the acetic acid writhing test model. Among the test compounds, compound III-3 (IC50 120 nmol·L-1) showed significant activity against MAGL and ameliorated the clinical progression in the mouse pain model. Additionally, compound III-3, substitution with N-methyl-2-morpholinoacetamide, demonstrated improved solubility relative to tanshinone IIA.
