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.

The endocannabinoid (eCB) system is a key modulator of glutamate release within limbic neurocircuitry and thus heavily modulates stress responsivity and adaptation. The ventral hippocampus (vHPC)-basolateral amygdala (BLA) circuit has been implicated in the expression of negative affective states following stress exposure and is modulated by retrograde eCB signaling. However, the mechanisms governing eCB release and the causal relationship between vHPC-BLA eCB signaling and stress-induced behavioral adaptations are not known. Here, we utilized in vivo optogenetic- and biosensor-based approaches to determine the temporal dynamics of activity-dependent and stress-induced eCB release at vHPC-BLA synapses. Furthermore, we demonstrate that genetic deletion of cannabinoid type-1 receptors selectively at vHPC-BLA synapses decreases active stress coping and exacerbates stress-induced avoidance and anhedonia phenotypes. These data establish the in vivo determinants of eCB release at limbic synapses and demonstrate that eCB signaling within vHPC-BLA circuitry serves to counteract adverse behavioral consequences of stress.

Background: Despite the successful introduction of combined antiretroviral therapy, the prevalence of mild to moderate forms of HIV-associated neurocognitive disorders (HAND) remains high. It has been demonstrated that neuronal injury caused by HIV is excitotoxic and inflammatory, and it correlates with neurocognitive decline in HAND. Endocannabinoid system (ECS) protects the body from excitotoxicity and neuroinflammation on demand and presents a promising therapeutic target for treating HAND. Here, we firstly discuss the potential pathogenesis of HAND. We secondly discuss the structural and functional changes in the ECS that are currently known among HAND patients. We thirdly discuss current clinical and preclinical findings concerning the neuroprotective and anti-inflammatory properties of the ECS among HAND patients. Fourth, we will discuss the interactions between the ECS and neuroendocrine systems, including the hypothalamic-pituitary-adrenocortical (HPA) and hypothalamic-pituitary-gonadal (HPG) axes under the HAND conditions. Materials and Methods: We have carried out a review of the literature using PubMed to summarize the current state of knowledge on the association between ECS and HAND. Results: The ECS may be ideally suited for modulation of HAND pathophysiology. Direct activation of presynaptic cannabinoid receptor 1 or reduction of cannabinoid metabolism attenuates HAND excitotoxicity. Chronic neuroinflammation associated with HAND can be reduced by activating cannabinoid receptor 2 on immune cells. The sensitivity of the ECS to HIV may be enhanced by increased cannabinoid receptor expression in HAND. In addition, indirect regulation of the ECS through modulation of hormone-related receptors may be a potential strategy to influence the ECS and also alleviate the progression of HAND due to the reciprocal inhibition of the ECS by the HPA and HPG axes. Conclusions: Taken together, targeting the ECS may be a promising strategy to alleviate the inflammation and neurodegeneration caused by HIV-1 infection. Further studies are required to clarify the role of endocannabinoid signaling in HIV neurotoxicity. Strategies promoting endocannabinoid signaling may slow down cognitive decline of HAND are proposed.

In this work, 2-AG was successfully detected in human plasma samples using a new sandwich-type electrochemical immune device based on poly-β-cyclodextrin P(β-CD) functionalized with AuNPs-DDT and toluidine blue. The P(β-CD) ensured the bioactivity and stability of the immobilized 2-AG antibody by providing a broad surface for the efficient immobilization of the biotinylated antibody. To complete the top section of the immunosensor (reporter), an HRP-conjugated antibody of 2-AG (secondary antibody (Ab2)) was attached to the surface of a glassy carbon electrode (GCE) modified by P(β-CD), as well as a primarily biotinylated antibody (Ab1). The biosensor fabrication process was monitored using field-emission scanning electron microscope (FE-SEM) and EDS methods. Using the differential pulse voltammetry technique, the immunosensor was utilized for detection of 2-AG in real samples. The suggested interface increased the surface area, which allowed for the immobilization of a large quantity of anti-2-AG antibody while also improving biocompatibility, stability, and electrical conductivity. Finally, the suggested immunosensor\'s limit of quantitation was determined to be 0.0078 ng/L, with a linear range of 0.0078 to 1.0 ng/L. The results showed that the suggested bioassay can be utilized for diagnosis of 2-AG in clinical samples as a unique and ultrasensitive electrochemical biodevice.

Diabetic cardiomyopathy (DM) is the cause of late cardiac dysfunction in diabetic patients. Myocardial fibrosis is the main pathological mechanism, and it is associated with transforming growth factor-β1(TGF-β1) expression up-regulation. 2-Arachidonoylglycerol (2-AG) is an endogenous cannabinoid that can effectively improve myocardial cell energy metabolism and cardiac function. Here, we evaluated the protective effect of 2-AG on diabetic cardiomyopathy.
Male C57BL/6 mice were injected with 2-AG intraperitoneally for 4 weeks (10 micro g/kg/day) after 12 weeks of diabetic modeling. After 4 weeks, heart function was evaluated by echocardiography. Heart structure was assessed by hematoxylin and eosin staining. Cardiac fibrosis was analyzed using immunohistochemistry, Sirius red stain, and western blot.
After modeling in diabetic mice, cardiac ultrasonography showed decreased cardiac function and pathological findings showed myocardial fibrosis. 2-AG could effectively inhibit the up-regulation of TGF-β1 and Smad2/3, reduce myocardial fibrosis, and ultimately improve cardiac function in diabetic mice.
2-AG reduces cardiac fibrosis via the TGF-β1/Smad2/3 pathway and is a potential pathway for the treatment of cardiac dysfunction in diabetic mice.

OBJECTIVE: To investigate the modulatory effect of 2-arachidonoylglycerol (2-AG) on voltage-gated sodium currents(VGSCs) in rat caudate nucleus (CN) neurons with kainic acid (KA)-induced injury and explore the molecular mechanism underlying the neuroprotective effect of 2-AG.
METHODS: Primary cultures of CN neurons isolated from neonatal SD rats were treated with KA, 2-AG+KA, RIM (a CB1 receptor antagonist) +2-AG+KA, or vehicle only (as control).After 7 days in primary culture, the neurons were treated with corresponding agents for 12 h (RIM and 2-AG were added at the same time; KA was added 30 min later) before recording of current density changes, current-voltage characteristics, activation and inactivation kinetics of VGSCs (INa) using whole-cell patch clamp technique.
RESULTS: In cultured CN neurons, KA significantly increased current density of VGSCs (P=0.009) as compared with vehicle treatment.KA also produced a hyperpolarizing shift in the activation curve of INa and significantly increased the absolute value of V1/2 for activation (P=0.008).Addition of 2-AG in the culture medium obviously prevented KA-induced increase of INa (P=0.009) and hyperpolarizing shift in the activation curve of INa, and significantly reduced the value of V1/2 for activation(P=0.009)in a CB1 receptor-dependent manner.2-AG alone did not affect the density, activation or deactivation of VGSCs in rat CN neurons.
CONCLUSIONS: In excitotoxic events, endogenous 2-AG can offer neuroprotection by modulating VGSCs in the CN neurons through a CB1 receptor-dependent pathway.

Electroconvulsive therapy (ECT) is one of the most effective treatments for depression, but it can cause cognitive deficit. Unfortunately, effective preventive measures are still lacking. The endocannabinoid system is thought to play a key role in regulation of cognitive process. Whether the endocannabinoid system is involved in the learning and memory impairment caused by ECS remain unclear. In this work, we first found that cannabinoid receptor type 1 (CB1R) and 2-arachidonoylglycerol (2-AG) were strongly expressed in hippocampus by electroconvulsive shock (ECS) in a rat depression model established by chronic mild stress (CMS). Pharmacological inhibition of CB1R using AM251 in vivo resulted in a pronounced relief in ECS-induced spatial learning and memory impairment as well as in a marked reversal of impaired hippocampal long-term potentiation (LTP), and reduced synapse-related proteins expression. Furthermore, results of sucrose preference test (SPT) and open-field test (OFT) showed that AM251 had no significant impact on the therapeutic effects of ECS on pleasure and psychomotor activity. Taken together, we identified that CB1R is involved in the ECS-induced spatial learning and memory impairment and Inhibition of CB1R facilitates the recovery of memory impairment and hippocampal synaptic plasticity, without interfering with the therapeutic effects of ECS in depressed rats.

The endocannabinoid 2-arachidonoylglycerol (2-AG) is an anti-nociceptive lipid, which is inactivated through cellular uptake and subsequent catabolism by monoacylglycerol lipase (MAGL). The present study aimed to explore the effects of inhibition of MAGL on intestinal permeability. We first tested it in differentiated CaCO2 cells after 21 days\' culture. The rat model of water avoidance stress (WAS) was established, and rats were divided into four groups according to intervention. Rats received intraperitoneal injection (i.p.) of an MAGL inhibitor (JZL184) alone, JZL184 and a the cannabinoid receptor 1 (CB1) receptor antagonist (SR141716A), JZL184 and a cannabinoid receptor 2 (CB2) receptor antagonist (AM630) or vehicle alone (control). We analyzed the fluorescein isothiocyanate-dextran (FD4) permeability and 2-AG level. Expression of MAGL and tight-junction-associated proteins were detected by western blot. Compared with the control group, MAGL expression was higher and 2-AG levels lower among WAS rats. Intestinal permeability was increased following administration of JZL184 which occurred due to up-regulation of tight-junction-associated proteins Claudin-1, Claudin-2, Claudin-5 and Occludin. The effects of MAGL inhibition were mediated by CB1, indicating that MAGL may represent a novel target for the treatment of reduced intestinal permeability in the context of chronic stress.

UNASSIGNED: In this study, the neuroprotective mechanism of 2-arachidonoylglycerol 2-AG against non-caspase-dependent apoptosis in mice hippocampal neurons following MCAO was investigated.
UNASSIGNED: One hundred and fifty healthy clean male C57BL/6 mice were randomly divided into 3 groups: sham group, model group and 2-AG treatment group, 50 mice in each group. A modified Zea Longa method was used to establish a model of middle cerebral artery occlusion (MCAO) in mice. The apoptosis rate and mitochondrial membrane potential of hippocampal nerve cells were measured by flow cytometry. The mRNA expressions of AIF, Endo G and BNIP3 in hippocampal tissues were determined by qPCR. Western blot was used to determine the protein expressions of AIF, Endo G and BNIP3 in the mitochondria of hippocampal tissue.
UNASSIGNED: The apoptosis rate of hippocampal neurons in the group treated with 2-AG was significantly lower than that of the model (P<0.01), which indicated that 2-AG could inhibit the apoptosis of hippocampal neurons induced by MCAO. However, the mitochondrial membrane potential of hippocampal neurons in the group treated with 2-AG was significantly higher than that of the model (P<0.01), indicating that 2-AG could improve the mitochondrial membrane potential of hippocampal neurons in MCAO mice. Real-time quantitative PCR (qPCR) showed that 2-AG could inhibit the gene expressions of AIF, Endo G and BNIP3 in hippocampal tissues. Western blot results showed that 2-AG could inhibit the secretions of AIF, Endo G and BNIP3 into cytoplasm in mitochondria.
UNASSIGNED: Endocannabinoids 2-AG had a protective effect on neurons injury, and the mechanism was possibly associated with the protection of the brain nerve cells in the hippocampus and the integrity of the mitochondrial function. Endocannabinoids 2-AG may inhibit the non-caspase-dependent apoptosis pathway, so as to exert its nerve protective effect.

The pancreatic ductal adenocarcinoma (PDAC) microenvironment plays a critical role in the antitumor immune response. 2-arachidonoylglycerol (2-AG) exhibits a direct antitumor effect in various tumor models. However, the immunomodulatory effect of 2-AG on PDAC remains obscure. The aim of this study was to explore the tumor microenvironment response to 2-AG in pancreatic cancer. A PDAC orthotopic tumor model was used to investigate tumor proliferation and the population of immune cells in vivo, including dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), CD8+ T cells and CD4+ T cells. The effect of 2-AG on panc02 cell proliferation and DC2.4 cell maturation in vitro by mediating activation the typical cannabinoid receptors (CB1, CB2) was evaluated by flow cytometry and CCK8. The protein levels of P-STAT6, STAT6 and GADPH were measured by Western blotting.2-AG inhibited pancreatic cancer cell proliferation in tumor bearing mice and panc02 cell. Inhibition of proliferation was blocked by the CB1receptor antagonist (AM251) but not the CB2 receptor antagonist (AM630). In addition, 2-AG promoted DC phenotypic maturation and the production of proinflammatory cytokines by up-regulating p-STAT6. These effects were also blocked by AM251 but not AM630. Moreover, we also provide evidence that 2-AG administration induced the expansion of MDSCs in tumor bearing mice. However, no effect on the population of CD8+ T cells and CD4+ T cells was observed. Our findings support 2-AG exhibited direct antitumor effects via inhibiting pancreatic cancer proliferation and inducing DC phenotypic maturation, but also significantly promoted an immunosuppressive microenvironment via increasing the suppressive immune cell population of MDSCs.