Discovery of a Novel ASM Direct Inhibitor with a 1,5-Diphenyl-pyrazole Scaffold and Its Antidepressant Mechanism of Action.

Multiple studies have confirmed that acid sphingomyelinase (ASM) activity is associated with depression. The discovery of direct inhibitors against ASM is of great significance for exploring antidepressants and their mechanisms of action. Herein, a series of novel phenylpyrazole analogues were rationally designed and synthesized. Among them, compound 46 exhibited potent inhibitory activity (IC50 = 0.87 µM) and good drug-like properties. In vivo studies demonstrated that compound 46 was involved in multiple antidepressant mechanisms of action, which were associated with a decline of ceramide, including increasing the Bcl-2/Bax ratio and BDNF expression, down-regulating caspase-3 and caspase-9, ameliorating oxidative stress, reducing the levels of proinflammatory cytokines such as TNF-α, IL-1ß, and IL-6, and elevating 5-HT levels in the brains of mice, respectively. These meaningful results reveal for the first time that direct inhibitors exhibit remarkable antidepressant effects in the CUMS-induced mouse model through multiple mechanisms of antidepressant action.

Discovery of a novel class of reversible monoacylglycerol lipase inhibitors for potential treatment of depression.

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.

Lead compounds and key residues of ribosomal protein S1 in drug-resistant Mycobacterium tuberculosis.

Ribosomal protein S1 (RpsA) has been identified as a novel target of pyrazinoic acid (POA), which is the active form of pyrazinamide (PZA), in vivo. RpsA plays a crucial role in trans-translation, which is widespread in microbes. In our investigation, we first described the discovery of promising RpsA antagonists for drug-resistant mycobacterium (MtRpsAd438A) and M. smegmatis, as well as wild-type M. tuberculosis. These antagonists were discovered via structure/ligand-based virtual screening approaches. A total of 21 targeted compounds were selected by virtual screening, combined scores, affinity, similarities and rules for potential as drugs. Next, the affinities of these compounds for three targeted proteins were tested in vitro by applying various technologies, including fluorescence quenching titration (FQT), saturation transfer difference (STD), and chemical shift perturbation (CSP) assays. The results showed that seven compounds had a high affinity for the targeted proteins. Our discovery set the stage for discovering new chemical entities (NCEs) for PZA-resistant tuberculosis and providing key residues for rational drug design to target RpsA.