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.

Multiple medicinal chemistry strategies of targeting KRAS: State-of-the art and future directions.

KRAS is the most frequently mutated oncogene and drives the development and progression of malignancies, most notably non-small cell lung cancer (NSCLS), pancreatic ductal adenocarcinoma (PDAC) and colorectal cancer (CRC). However, KRAS proteins have maintained the reputation of being "undruggable" due to the lack of suitable deep pockets on its surface. One major milestone for KRAS inhibition was the discovery of the covalent inhibitors bond to the allosteric switch-II pocket of the KRASG12C protein. To date, the FDA has approved two KRASG12C inhibitors, sotorasib and adagrasib, for the treatment of patients with KRASG12C-driven cancers. Researchers have paid close attention to the development of inhibitors for other KRAS mutations and upstream regulatory factors. The KRAS targeted drug discovery has entered a state of rapid development. This article has aimed to present the current state of the art of drug development in the KRAS field. We systematically summarize recent advances in the discovery and optimization processes of direct KRAS inhibitors (including KRASG12C, KRASG12D, KRASG12A and KRASG12R inhibitors), indirect KRAS inhibitors (SOS1 and SHP2 inhibitors), pan-KRAS inhibitors, as well as proteolysis-targetingchimeras degrades and molecular chaperone modulators from the perspective of medicinal chemistry. We also discuss the current challenges and opportunities of KRAS inhibition and hope to shed light on future KRAS drug discovery.

Hybrids of selective COX-2 inhibitors and active derivatives of edaravone as COX-2 selective NSAIDs with free radical scavenging activity: Design, synthesis and biological activities.

Novel hybrids of selective COX-2 inhibitors (coxibs) and active derivatives of free radical scavenger edaravone were designed to overcome the risk of cardiovascular events and stroke increased by NSAIDs (nonsteroidal anti-inflammatory drugs) in this study. All the hybrids were assayed for the COX-2 inhibitory and DPPH (2, 2-diphenyl-1-picrylhydrazyl) free radical scavenging activities in vitro. Finally, we found a series of hybrids with good inhibitory activity and selectivity of COX-2 and excellent free radical scavenging activity in vitro. The most promising compound 6a (WYZ90) exhibited very potent COX-2 inhibitory activity (COX-2, IC50 = 75 nM), weak COX-1 inhibitory activity (COX-1, IC50 = 5734 nM), better free radical scavenging activity (DPPH, IC50 = 19.9 µM) than edaravone, moderate drug-likeness and ADME properties in silico, acceptable pharmacokinetic properties (T1/2 = 4.16 h, 10 mg/kg, o.p.) and oral bioavailability (F% = 36.03 %) in mice. In addition, compound WYZ90 showed similar analgesic activity to the selective COX-2 inhibitor celecoxib in acetic acid-induced mice and better antioxidant activity in Fe2+-induced lipid peroxidation in mouse liver tissue homogenate than edaravone. In conclusion, this study provided a novel class of coxibs containing edaravone moiety as COX-2 selective NSAIDs with free radical scavenging activity and the candidate compound WYZ90 showed not only similar selective COX-2 inhibitory and analgesic activity to celecoxib but also better free radical scavenging and antioxidant activity than edaravone.

Design and synthesis of a novel class of PDE4 inhibitors with antioxidant properties as bifunctional agents for the potential treatment of COPD.

It is well known that chronic obstructive pulmonary disease (COPD) patients are always trapped in the vicious circle of inflammation and oxidative stress, therefore anti-inflammatory and antioxidant bifunctional agents may interrupt this vicious cycle in COPD. Phosphodiesterase 4 (PDE4) inhibitors, as anti-inflammatory drugs, have been used for COPD treatment in clinical, and the PDE4 inhibitors with antioxidant properties may be a good strategy to design bifunctional agents for COPD. Sappanone A was the first PDE4 inhibitor with antioxidant properties we identified from natural products in our previous study, which was used by us as a hit compound to design new bifunctional agents for COPD in this study. 27 derivatives of sappanone A including homoisoflavonoids, aurones and chalcones were designed and synthesized by innovatively fusing the antioxidant pharmacophore of catechol from polyphenols and the pharmacophore of catechol ether abstracted from the PDE4 inhibitors of the catechol ether class such as rolipram, roflumilast and apremilast respectively. All the compounds were assayed for the PDE4 inhibitory and radical scavenging against 2, 2-diphenyl-1-picrylhydrazyl (DPPH) activities in vitro. Herein we obtained a series of bifunctional compounds with better PDE4 inhibitory activity than sappanone A, and their free radical scavenging activities were superior to edaravone in vitro. In addition, they can reduce tumour necrosis factor-alpha (TNF-α) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophages and malondialdehyde (MDA) production induced by Fe2+ in mouse lung homogenate. Meanwhile, it showed outstanding abilities in reducing Fe3+ and complexing Fe2+. 6o, as the candidate anti-inflammatory and antioxidant bifunctional compound, exhibited good drug-likeness, ADME (Absorption, Distribution, Metabolism, Excretion) properties and human liver microsomal stability. In vivo, 6o (50 mg/kg and 100 mg/kg, i. p.) distinctly prevented LPS-induced serum levels of TNF-α in mice. In conclusion, the preliminary investigation provided a novel class of PDE4 inhibitors with antioxidant properties as bifunctional agents for the potential treatment of COPD, which can interrupt the vicious cycle of chronic inflammation and oxidative stress in COPD.

Development of indole-2-carbonyl piperazine urea derivatives as selective FAAH inhibitors for efficient treatment of depression and pain.

Fatty acid amide hydrolase (FAAH), aserinehydrolase with significant role in thehydrolysis of endocannabinoids, is a promising therapeutic target for peripheral and central nervous system related disorders, including pain, neuroinflammation and depression. Employing a structure-based approach, a novel series of indole-2-carbonyl piperazine urea derivatives were designed and synthesized as FAAH inhibitors for the treatment of pain-depression comorbidity. Among them, compound 4i emerged as the most potent inhibitor (IC50 = 0.12 µM) with fine selectivity versus CES2, ABHD6, MAGL and the cannabinoid receptor, which also displayed superior metabolic stability in human liver microsome and an adequate pharmacokinetic profile in rodents. Treatment of depressed rats with 4i demonstrated favorable antidepressant-like effects not only by increasing the level of BDNF in the hippocampus but also by restraining the apoptosis of hippocampal neurons. Also, 4i effectively suppressed the LPS-induced neuroinflammation in vitro. Moreover, 4i exhibited potent analgesic activity, which indicated its promising therapeutical application for pain and depression. These meaningful results shed light on FAAH inhibitors as promising pain-depression comorbidity therapeutics.

Discovery of Aryl Formyl Piperidine Derivatives as Potent, Reversible, and Selective Monoacylglycerol Lipase Inhibitors.

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.

Discovery of heterocyclic carbohydrazide derivatives as novel selective fatty acid amide hydrolase inhibitors: design, synthesis and anti-neuroinflammatory evaluation.

Fatty acid amide hydrolase (FAAH) is a promising target for the development of drugs to treat pain, inflammation, and other central nervous system disorders. Herein, a series of novel heterocyclic carbohydrazide derivatives were firstly designed by the classic scaffold-hopping strategy. Then, multi-steps synthesis and human FAAH enzyme inhibiting activity assays were conducted. Among them, compound 26 showedstrong inhibition against human FAAH with IC50 of 2.8 µM. Corresponding docking studies revealed that the acyl hydrazide group of compound 26 well-occupied the acyl-chain binding pocket. It also exhibited high selectivity towards FAAH when comparing with CES2 and MAGL. Additionally, compound 26 effectively suppressed the LPS-induced neuroinflammation of microglial cells (BV2) via the reduction of interleukin-1ß and tumor necrosis factor-α. Our results provided significative lead compounds for the further discovery of novel selective and safe FAAH inhibitors with potent anti-neuroinflammation activity.