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Atypical Usher syndrome (USH) is poorly defined with a broad clinical spectrum. Here, we characterize the clinical phenotype of disease caused by variants in CEP78, CEP250, ARSG, and ABHD12.Chart review evaluating demographic, clinical, imaging, and genetic findings of 19 patients from 18 families with a clinical diagnosis of retinal disease and confirmed disease-causing variants in CEP78, CEP250, ARSG, or ABHD12.CEP78-related disease included sensorineural hearing loss (SNHL) in 6/7 patients and demonstrated a broad phenotypic spectrum including: vascular attenuation, pallor of the optic disc, intraretinal pigment, retinal pigment epithelium mottling, areas of mid-peripheral hypo-autofluorescence, outer retinal atrophy, mild pigmentary changes in the macula, foveal hypo-autofluorescence, and granularity of the ellipsoid zone. Nonsense and frameshift variants in CEP250 showed mild retinal disease with progressive, non-congenital SNHL. ARSG variants resulted in a characteristic pericentral pattern of hypo-autofluorescence with one patient reporting non-congenital SNHL. ABHD12-related disease showed rod-cone dystrophy with macular involvement, early and severe decreased best corrected visual acuity, and non-congenital SNHL ranging from unreported to severe.This study serves to expand the clinical phenotypes of atypical USH. Given the variable findings, atypical USH should be considered in patients with peripheral and macular retinal disease even without the typical RP phenotype especially when SNHL is noted. Additionally, genetic screening may be useful in patients who have clinical symptoms and retinal findings even in the absence of known SNHL given the variability of atypical USH.

Endocannabinoids are host-derived lipid hormones that fundamentally impact gastrointestinal (GI) biology. The use of cannabis and other exocannabinoids as anecdotal treatments for various GI disorders inspired the search for mechanisms by which these compounds mediate their effects, which led to the discovery of the mammalian endocannabinoid system. Dysregulated endocannabinoid signaling was linked to inflammation and the gut microbiota. However, the effects of endocannabinoids on host susceptibility to infection has not been explored. Here, we show that mice with elevated levels of the endocannabinoid 2-arachidonoyl glycerol (2-AG) are protected from enteric infection by Enterobacteriaceae pathogens. 2-AG directly modulates pathogen function by inhibiting virulence programs essential for successful infection. Furthermore, 2-AG antagonizes the bacterial receptor QseC, a histidine kinase encoded within the core Enterobacteriaceae genome that promotes the activation of pathogen-associated type three secretion systems. Taken together, our findings establish that endocannabinoids are directly sensed by bacteria and can modulate bacterial function.

The endocannabinoid system is a key regulator of the response to psychological stress. Inhibitors of monoacylglycerol lipase (MGL), the enzyme that deactivates the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG), exert anxiolytic-like effects in rodent models via 2-AG-dependent activation of CB1 cannabinoid receptors. In the present study, we examined whether the MGL inhibitor JZL184 might modulate persistent predator-induced fear in rats, a model that captures features of human post-traumatic stress disorder. Exposure to 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), a volatile chemical that is innately aversive to some rodent species, produced in male rats a long-lasting anxiety-like state that was measured 7 days later in the elevated plus maze test. Systemic administration of JZL184 [4, 8 and 16 mg/kg, intraperitoneal (IP)] 4 h before testing caused dose-dependent inhibition of MGL activity and elevation of 2-AG content in brain tissue. Concomitantly, the inhibitor suppressed TMT-induced fear behaviors with a median effective dose (ED50) of 4 mg/kg. A similar behavioral response was observed with another MGL inhibitor, KML29 (4 and 16 mg/kg, IP). Surprisingly, the effect of JZL184 was prevented by co-administration of the CB2 inverse agonist AM630 (5 mg/kg, IP), but not the CB1 inverse agonist rimonabant (1 mg/kg, IP). Supporting mediation of the response by CB2 receptors, the CB2 agonist JWH133 (0.3, 1 and 3 mg/kg, IP) also produced anxiolytic-like effects in TMT-stressed rats, which were suppressed by AM630. Notably, (i) JWH133 was behaviorally ineffective in animals that had no prior experience with TMT; and (ii) CB2 mRNA levels in rat prefrontal cortex were elevated 7 days after exposure to the aversive odorant. The results suggest that JZL184 attenuates the behavioral consequences of predator stress through a mechanism that requires 2-AG-mediated activation of CB2 receptors, whose transcription may be induced by the stress itself.

Phenotypic screening has identified small-molecule modulators of aging, but the mechanism of compound action often remains opaque due to the complexities of mapping protein targets in whole organisms. Here, we combine a library of covalent inhibitors with activity-based protein profiling to coordinately discover bioactive compounds and protein targets that extend lifespan in Caenorhabditis elegans. We identify JZL184-an inhibitor of the mammalian endocannabinoid (eCB) hydrolase monoacylglycerol lipase (MAGL or MGLL)-as a potent inducer of longevity, a result that was initially perplexing as C. elegans does not possess an MAGL ortholog. We instead identify FAAH-4 as a principal target of JZL184 and show that this enzyme, despite lacking homology with MAGL, performs the equivalent metabolic function of degrading eCB-related monoacylglycerides in C. elegans. Small-molecule phenotypic screening thus illuminates pure pharmacological connections marking convergent metabolic functions in distantly related organisms, implicating the FAAH-4/monoacylglyceride pathway as a regulator of lifespan in C. elegans.

The function of monoacylglycerol lipase (MGL), a key actor in the hydrolytic deactivation of the endocannabinoid 2-arachidonoyl-sn-glycerol (2AG), is tightly controlled by the cell's redox state: oxidative signals such as hydrogen peroxide suppress MGL activity in a reversible manner through sulfenylation of the peroxidatic cysteines, C201 and C208. Here, using as a starting point the crystal structures of human MGL (hMGL), we present evidence from molecular dynamics and metadynamics simulations along with high-resolution mass spectrometry studies indicating that sulfenylation of C201 and C208 alters the conformational equilibrium of the membrane-associated lid domain of MGL to favour closed conformations of the enzyme that do not permit the entry of substrate into the active site.

The endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG), a key modulator of synaptic transmission in mammalian brain, is produced in dendritic spines and then crosses the synaptic junction to depress neurotransmitter release. Here we report that 2-AG-dependent retrograde signaling also mediates an enduring enhancement of glutamate release, as assessed with independent tests, in the lateral perforant path (LPP), one of two cortical inputs to the granule cells of the dentate gyrus. Induction of this form of long-term potentiation (LTP) involved two types of glutamate receptors, changes in postsynaptic calcium, and the postsynaptic enzyme that synthesizes 2-AG. Stochastic optical reconstruction microscopy confirmed that CB1 cannabinoid receptors are localized presynaptically to LPP terminals, while the inhibition or knockout of the receptors eliminated LPP-LTP. Suppressing the enzyme that degrades 2-AG dramatically enhanced LPP potentiation, while overexpressing it produced the opposite effect. Priming with a CB1 agonist markedly reduced the threshold for LTP. Latrunculin A, which prevents actin polymerization, blocked LPP-LTP when applied extracellularly but had no effect when infused postsynaptically into granule cells, indicating that critical actin remodeling resides in the presynaptic compartment. Importantly, there was no evidence for the LPP form of potentiation in the Schaffer-commissural innervation of field CA1 or in the medial perforant path. Peripheral injections of compounds that block or enhance LPP-LTP had corresponding effects on the formation of long-term memory for cues conveyed to the dentate gyrus by the LPP. Together, these results indicate that the encoding of information carried by a principal hippocampal afferent involves an unusual, regionally differentiated form of plasticity.

RATIONALE: The endocannabinoid system is an important modulator of brain reward signaling. Investigations have focused on cannabinoid (CB1) receptors, because dissection of specific contributions of individual endocannabinoids has been limited by the available toolset. While we recently described an important role for the endocannabinoid anandamide in the regulation of social reward, it remains to be determined whether the other major endocannabinoid, 2-arachidonoyl-sn-glycerol (2-AG), serves a similar or different function. OBJECTIVES: To study the role of 2-AG in natural reward, we used a transgenic mouse model (MGL-Tg mice) in which forebrain 2-AG levels are selectively reduced. We complemented behavioral analysis with measurements of brain 2-AG levels. METHODS: We tested male MGL-Tg mice in conditioned place preference (CPP) tasks for high-fat food, social contact, and cocaine. We measured 2-AG content in the brain regions of interest by liquid chromatography/mass spectrometry. RESULTS: Male MGL-Tg mice are impaired in developing CPP for high-fat food and social interaction, but do develop CPP for cocaine. Furthermore, compared to isolated mice, levels of 2-AG in socially stimulated wild-type mice are higher in the nucleus accumbens and ventral hippocampus (183 and 140 % of controls, respectively), but unchanged in the medial prefrontal cortex. CONCLUSIONS: The results suggest that reducing 2-AG-mediated endocannabinoid signaling impairs social and high-fat food reward in male mice, and that social stimulation mobilizes 2-AG in key brain regions implicated in the control of motivated behavior. The time course of this response differentiates 2-AG from anandamide, whose role in mediating social reward was previously documented.

RationaleManipulations of the endocannabinoid system could potentially produce therapeutic effects with minimal risk of adverse cannabis-like side effects. Inhibitors of fatty acid amide hydrolase (FAAH) increase endogenous levels of the cannabinoid-receptor agonist, anandamide, and show promise for treating a wide range of disorders. However, their effects on learning and memory have not been fully characterized.ObjectivesWe determined the effects of five structurally different FAAH inhibitors in an animal model of working memory known to be sensitive to impairment by delta-9 tetrahydrocannabinol (THC).MethodsA delayed nonmatching-to-position procedure was used in rats. Illuminated nosepoke holes were used to provide sample cues (left versus right) and record responses (correct versus incorrect) after delays ranging from 0 to 28 s. Various test drugs were given acutely up to two times per week before daily sessions.ResultsOne FAAH inhibitor, AM3506 (3 mg/kg), decreased accuracy in the memory task. Four other FAAH inhibitors (URB597, URB694, PF-04457845, and ARN14633) and a monoacylglycerol lipase inhibitor (JZL184, which blocks the degradation of the endocannabinoid 2-arachidonoylglycerol) had no effect. Testing of AM3506 in combination with antagonists for receptors known to be affected by anandamide and other fatty acid amides indicated that the impairment induced by AM3506 was mediated by cannabinoid CB1 receptors, and not by alpha-type peroxisome proliferator-activated receptors (PPAR-alpha) or vanilloid transient receptor potential cation channels (TRPV1).ConclusionsFAAH inhibitors differ with respect to their potential for memory impairment, abuse liability, and probably other cannabis-like effects, and they should be evaluated individually for specific therapeutic and adverse effects.

Monoglyceride lipase (MGL), the main enzyme responsible for the hydrolytic deactivation of the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG), is an intracellular serine hydrolase that plays critical roles in many physiological and pathological processes, such as pain, inflammation, neuroprotection and cancer. The crystal structures of MGL that are currently available provide valuable information about how this enzyme might function and interact with site-directed small-molecule inhibitors. On the other hand, its conformational equilibria and the contribution of regulatory cysteine residues present within the substrate-binding pocket or on protein surface remain open issues. Several classes of MGL inhibitors have been developed, from early reversible ones, such as URB602 and pristimerin, to carbamoylating agents that react with the catalytic serine, such as JZL184 and more recent O-hexafluoroisopropyl carbamates. Other inhibitors that modulate MGL activity by interacting with conserved regulatory cysteines act through mechanisms that deserve to be more thoroughly investigated.

Individuals who experience life-threatening psychological trauma are at risk of developing a series of chronic neuropsychiatric pathologies that include generalized anxiety, depression, and drug addiction. The endocannabinoid system has been implicated in the modulation of these responses by regulating the activity of the amygdala and the hypothalamic-pituitary-adrenal axis. However, the relevance of this signaling complex to the long-term consequences of traumatic events is unclear. Here we use an animal model of predatory stress-induced anxiety-like behavior to investigate the role of the endocannabinoid system in the development of persistent anxiety states. Our main finding is that rats exposed to the fox pheromone 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), a life-threatening stimulus for rodents, display a marked and selective increase in the mobilization of the endocannabinoid, 2-arachidonoyl-sn-glycerol (2-AG), in the amygdala. This effect lasts for at least 14 days after the stress has occurred. In addition, systemic or local pharmacological inhibition of monoacylglycerol lipase (MGL)-a lipid hydrolase that degrades 2-AG in presynaptic nerve terminals-elevates 2-AG levels and suppresses the anxiety-like behavior elicited by exposure to TMT. The results suggest that predator threat triggers long-term changes in 2-AG-mediated endocannabinoid signaling in the amygdala, and that pharmacological interventions targeting MGL might provide a therapeutic strategy for the treatment of chronic brain disorders initiated by trauma.

We report the discovery of compound 4a, a potent β-lactam-based monoacylglycerol lipase (MGL) inhibitor characterized by an irreversible and stereoselective mechanism of action, high membrane permeability, high brain penetration evaluated using a human in vitro blood-brain barrier model, high selectivity in binding and affinity-based proteomic profiling assays, and low in vitro toxicity. Mode-of-action studies demonstrate that 4a, by blocking MGL, increases 2-arachidonoylglycerol and behaves as a cannabinoid (CB1/CB2) receptor indirect agonist. Administration of 4a in mice suffering from experimental autoimmune encephalitis ameliorates the severity of the clinical symptoms in a CB1/CB2-dependent manner. Moreover, 4a produced analgesic effects in a rodent model of acute inflammatory pain, which was antagonized by CB1 and CB2 receptor antagonists/inverse agonists. 4a also relieves the neuropathic hypersensitivity induced by oxaliplatin. Given these evidence, 4a, as MGL selective inhibitor, could represent a valuable lead for the future development of therapeutic options for multiple sclerosis and chronic pain.

Monoacylglycerol lipase (MGL) is a serine hydrolase involved in the biological deactivation of the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG). 2-AG is one of the main endogenous lipid agonists for cannabinoid receptors in the brain and elsewhere in the body. In the central nervous system (CNS), MGL is localized to presynaptic nerve terminals of both excitatory and inhibitory synapses, where it helps control the regulatory actions of 2-AG on synaptic transmission and plasticity. In this chapter, we describe an in vitro method to assess MGL activity by liquid chromatography/mass spectrometry (LC/MS)-based quantitation of the reaction product. This method may be used to determine the basal or altered MGL activity in various cells or animal tissues after pharmacological, genetic, or biological manipulations. In addition, this assay can be used for MGL inhibitor screening using purified recombinant enzyme or MGL-overexpressing cells.

The second messenger hydrogen peroxide transduces changes in the cellular redox state by reversibly oxidizing protein cysteine residues to sulfenic acid. This signaling event regulates many cellular processes but has never been shown to occur in the brain. Here, we report that hydrogen peroxide heightens endocannabinoid signaling in brain neurons through sulfenylation of cysteines C201 and C208 in monoacylglycerol lipase (MGL), a serine hydrolase that deactivates the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG) in nerve terminals. The results suggest that MGL sulfenylation may provide a presynaptic control point for 2-AG-mediated endocannabinoid signaling.

Human monoacylglycerol lipase (MGL) catalyzes the hydrolysis of 2-arachidonoylglycerol to arachidonic and glycerol, which plays a pivotal role in the normal biological processes of brain. Co-crystal structure of the MGL in complex with its inhibitor, compound 1, shows that the helix α4 undergoes large-scale conformational changes in response to the compound 1 binding compared to the apo MGL. However, the detailed conformational transition pathway of the helix α4 in the inhibitor binding process of MGL has remained unclear. Here, conventional molecular dynamics (MD) and nudged elastic band (NEB) simulations were performed to explore the conformational transition pathway of the helix α4. Conventional MD simulations unveiled that the compound 1 induced the closed conformation of the active site of MGL, reduced the conformational flexibility of the helix α4, and elicited the large-scale conformational rearrangement of the helix α4, leading to the complete folding of the helix α4. Moreover, NEB simulations revealed that the conformational transition pathway of helix α4 underwent an almost 180° counter-clockwise rotation of the helix α4. Our computational results advance the structural and mechanistic understanding of the inhibitory mechanism.

The endocannabinoid system, most popularly known as the target of the psychoactive component of marijuana, Δ(9)-tetrahydrocannabinol (THC), is a signaling network that modulates a diverse range of physiological processes including nociception, behavior, cognitive function, appetite, metabolism, motor control, memory formation, and inflammation. While THC and its derivatives have garnered notoriety in the eyes of the public, the endocannabinoid system consists of two endogenous signaling lipids, 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (anandamide), which activate cannabinoid receptors CB1 and CB2 in the nervous system and peripheral tissues. This review will focus on the recent efforts to chemically manipulate 2-AG signaling through the development of inhibitors of the 2-AG-synthesizing enzyme diacylglycerol lipase (DAGL) or the 2-AG-degrading enzyme monoacylglycerol lipase (MAGL), and assessing the therapeutic potential of DAGL and MAGL inhibitors in pain, inflammation, degenerative diseases, tissue injury, and cancer.

Objectives: Monoacylglycerol lipase (MAGL) is a cytosolic serine hydrolase considered a potential novel drug target for the treatment of CNS disorders including epilepsy. Here we examined MAGL levels in a rat model of epilepsy., Methods: Autoradiography has been used to validate the binding properties of the MAGL radiotracer, [ 3 H]T-401, in the rat brain, and to explore spatial and temporal changes in binding levels in a model of temporal lobe epilepsy model using unilateral intra-hippocampal injections of kainic acid (KA) in rats., Results: Specific and saturable binding of [ 3 H]T-401 was detected in both cortical grey and subcortical white matter. Saturation experiments revealed a K D in the range between 15 nM and 17 nM, and full saturation was achieved at concentrations around 30 nM. The binding could be completely blocked with the cold ligand (K i 44.2 nM) and at higher affinity (K i 1.27 nM) with another structurally different MAGL inhibitor, ABD 1970. Bilateral reduction in [ 3 H]T-401 binding was observed in the cerebral cortex and the hippocampus few days after status epilepticus that further declined to a level of around 30% compared to the control. No change in binding was observed in either the hypothalamus nor the white matter at any time point. Direct comparison to [ 3 H]UCB-J binding to synaptic vesicle glycoprotein 2 A (SV2A), another protein localized in the pre-synapse, revealed that while binding to MAGL remained low in the chronic phase, SV2A was increased significantly in some cortical areas., Significance: These data show that MAGL is reduced in the cerebral cortex and hippocampus in a chronic epilepsy model and indicate that MAGL inhibitors may further reduce MAGL activity in the treatment resistant epilepsy patient., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest relevant for this article., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Colorectal cancer (CRC) continues to be a prevalent malignancy, posing a significant risk to human health. The involvement of alpha/beta hydrolase domain 6 (ABHD6), a serine hydrolase family member, in CRC development was suggested by our analysis of clinical data. However, the role of ABHD6 in CRC remains unclear. This study seeks to elucidate the clinical relevance, biological function, and potential molecular mechanisms of ABHD6 in CRC. We investigated the role of ABHD6 in clinical settings, conducting proliferation, migration, and cell cycle assays. To determine the influence of ABHD6 expression levels on Oxaliplatin sensitivity, we also performed apoptosis assays. RNA sequencing and KEGG analysis were utilized to uncover the potential molecular mechanisms of ABHD6. Furthermore, we validated its expression levels using Western blot and reactive oxygen species (ROS) detection assays. Our results demonstrated that ABHD6 expression in CRC tissues was notably lower compared to adjacent normal tissues. This low expression correlated with a poorer prognosis for CRC patients. Moreover, ABHD6 overexpression impeded CRC cell proliferation and migration while inducing G0/G1 cell cycle arrest. In vivo experiments revealed that downregulation of ABHD6 resulted in an increase in tumor weight and volume. Mechanistically, ABHD6 overexpression inhibited the activation of the AKT signaling pathway and decreased ROS levels in CRC cells, suggesting the role of ABHD6 in CRC progression via the AKT signaling pathway. Our findings demonstrate that ABHD6 functions as a tumor suppressor, primarily by inhibiting the AKT signaling pathway. This role establishes ABHD6 as a promising prognostic biomarker and a potential therapeutic target for CRC patients., (© 2024 Wiley Periodicals LLC.)

BackgroundThe endocannabinoids are emerging as natural brain protective substances that exert potentially beneficial effects in several neurological disorders by virtue of their hypothermic, immunomodulatory, vascular, antioxidant, and antiapoptotic actions. This study was undertaken to assess whether preventing the deactivation of the endocannabinoid 2-arachidonoylglycerol (2-AG) with the monoacylglycerol lipase (MAGL) inhibitor URB602 can provide neuroprotective effects in hypoxia-ischemia (HI)-induced brain injury.MethodsURB602 was administered into the right lateral ventricle 30 min before 7-day-old pup rats were subjected to HI. The neuroprotective effect was evaluated on postnatal day (PN) 14 or at adulthood (PN80) using behavioral and histological analyses. Activated caspase-3 expression and propidium iodide labeling were assessed as indexes of apoptotic and necrotic cell death, respectively.ResultsPretreatment with URB602 reduced apoptotic and necrotic cell death, as well as the infarct volume measured at PN14. At adulthood, URB602-treated HI animals performed better at the T-maze and the Morris maze, and also showed a significant reduction of brain damage.ConclusionThese results demonstrate that a pretreatment with URB602 significantly reduces brain damage and improves functional outcome, indicating that endocannabinoid-degrading enzymes may represent an important target for neuroprotection in neonatal ischemic brain injury.

The endocannabinoid system plays a critical role in the control of energy homeostasis, but the identity and localization of the endocannabinoid signal involved remain unknown. In the present study, we developed transgenic mice that overexpress in forebrain neurons the presynaptic hydrolase, monoacylglycerol lipase (MGL), which deactivates the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG). MGL-overexpressing mice show a 50% decrease in forebrain 2-AG levels but no overt compensation in other endocannabinoid components. This biochemical abnormality is accompanied by a series of metabolic changes that include leanness, elevated energy cost of activity, and hypersensitivity to β(3)-adrenergic-stimulated thermogenesis, which is corrected by reinstating 2-AG activity at CB(1)-cannabinoid receptors. Additionally, the mutant mice are resistant to diet-induced obesity and express high levels of thermogenic proteins, such as uncoupling protein 1, in their brown adipose tissue. The results suggest that 2-AG signaling through CB(1) regulates the activity of forebrain neural circuits involved in the control of energy dissipation.

BACKGROUND AND PURPOSE The endocannabinoid 2-arachidonoylglycerol (2-AG) is degraded primarily by monoacylglycerol lipase (MGL). We compared peripheral antinociceptive effects of JZL184, a novel irreversible MGL inhibitor, with the reversible MGL-preferring inhibitor URB602 and exogenous 2-AG in rats. EXPERIMENTAL APPROACH Nociception in the formalin test was assessed in groups receiving dorsal paw injections of vehicle, JZL184 (0.001-300 µg), URB602 (0.001-600 µg), 2-AG (ED(50)), 2-AG + JZL184 (at their ED(50)), 2-AG + URB602 (at their ED(50)), AM251 (80 µg), AM251 + JZL184 (10 µg), AM630 (25 µg) or AM630 + JZL184 (10 µg). Effects of MGL inhibitors on endocannabinoid accumulation and on activities of endocannabinoid-metabolizing enzymes were assessed. KEY RESULTS Intra-paw administration of JZL184, URB602 and 2-AG suppressed early and late phases of formalin pain. JZL184 and URB602 acted through a common mechanism. JZL184 (ED(50) Phase 1: 0.06 ± 0.028; Phase 2: 0.03 ± 0.011 µg) produced greater antinociception than URB602 (ED(50) Phase 1: 120 ± 51.3; Phase 2: 66 ± 23.9 µg) or 2-AG. Both MGL inhibitors produced additive antinociceptive effects when combined with 2-AG. Antinociceptive effects of JZL184, like those of URB602, were blocked by cannabinoid receptor 1 (CB(1)) and cannabinoid receptor 2 (CB(2)) antagonists. JZL184 suppressed MGL but not fatty-acid amide hydrolase or N-arachidonoyl-phosphatidylethanolamine phospholipase D activities ex vivo. URB602 increased hind paw 2-AG without altering anandamide levels. CONCLUSIONS AND IMPLICATIONS MGL inhibitors suppressed formalin-induced pain through peripheral CB(1) and CB(2) receptor mechanisms. MGL inhibition increased paw skin 2-AG accumulation to mediate these effects. MGL represents a target for the treatment of inflammatory pain.

Peripheral cannabinoid receptors exert a powerful inhibitory control over pain initiation, but the endocannabinoid signal that normally engages this intrinsic analgesic mechanism is unknown. To address this question, we developed a peripherally restricted inhibitor (URB937) of fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of the endocannabinoid anandamide. URB937 suppressed FAAH activity and increased anandamide levels outside the rodent CNS. Despite its inability to access brain and spinal cord, URB937 attenuated behavioral responses indicative of persistent pain in rodent models of peripheral nerve injury and inflammation and prevented noxious stimulus-evoked neuronal activation in spinal cord regions implicated in nociceptive processing. CB₁ cannabinoid receptor blockade prevented these effects. These results suggest that anandamide-mediated signaling at peripheral CB₁ receptors controls the access of pain-related inputs to the CNS. Brain-impenetrant FAAH inhibitors, which strengthen this gating mechanism, might offer a new approach to pain therapy.

Monoacylglycerol lipase (MAGL) is a serine hydrolase that plays a crucial role catalysing the hydrolysis of monoglycerides into glycerol and fatty acids. It links the endocannabinoid and eicosanoid systems together by degradation of the abundant endocannabinoid 2-arachidaoylglycerol into arachidonic acid, the precursor of prostaglandins and other inflammatory mediators. MAGL inhibitors have been considered as important agents in many therapeutic fields, including anti-nociceptive, anxiolytic, anti-inflammatory, and even anti-cancer. Currently, ABX-1431, a first-in-class inhibitor of MAGL, is entering clinical phase 2 studies for neurological disorders and other diseases. This review summarizes the diverse (patho)physiological roles of MAGL and will provide an overview on the development of MAGL inhibitors. Although a large number of MAGL inhibitors have been reported, novel inhibitors are still required, particularly reversible ones. Monoacylglycerol lipase (MAGL) plays a crucial role catalysing the hydrolysis of monoglycerides. MAGL inhibitors have been considered as important agents in many therapeutic fields, including anti-nociceptive, anti-inflammatory and anti-cancer. The diverse (patho)physiological roles of MAGL and a comprehensive overview of reported MAGL inhibitors were summarized in this review. Image 1 [ABSTRACT FROM AUTHOR]

Monoacylglycerol lipase (MGL) is a serine hydrolase involved in the biological deactivation of the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG). Previous efforts to design MGL inhibitors have focused on chemical scaffolds that irreversibly block the activity of this enzyme. Here, we describe two naturally occurring terpenoids, pristimerin and euphol, which inhibit MGL activity with high potency (median effective concentration, IC(50) = 93 nM and 315 nM, respectively) through a reversible mechanism. Mutational and modeling studies suggest that the two agents occupy a common hydrophobic pocket located within the putative lid domain of MGL, and each reversibly interacts with one of two adjacent cysteine residues (Cys(201) and Cys(208)) flanking such pocket. This previously unrecognized regulatory region might offer a molecular target for potent and reversible inhibitors of MGL.

Background and purposeMonoacylglycerol lipase (MGL) is a presynaptic serine hydrolase that inactivates the endocannabinoid neurotransmitter, 2-arachidonoyl-sn-glycerol. Recent studies suggest that cysteine residues proximal to the enzyme active site are important for MGL function. In the present study, we characterize the role of cysteines in MGL function and identify a series of cysteine-reactive agents that inhibit MGL activity with nanomolar potencies by interacting with cysteine residue 208.Experimental approachA series of cysteine traps were screened for the ability to inhibit MGL in vitro. Rapid dilution assays were performed to determine reversibility of inhibition. Molecular modelling and site-directed mutagenesis were utilized to identify cysteine residues targeted by the inhibitors.Key resultsThe screening revealed that 2-octyl-4-isothiazolin-3-one (octhilinone) inhibited purified rat recombinant MGL (IC(50)= 88 +/- 12 nM) through a partially reversible mechanism. Initial structure-activity relationship studies showed that substitution of the n-octyl group of octhilinone with a more lipophilic oleoyl group increased inhibitor potency (IC(50)= 43 +/- 8 nM), while substitution with a methyl group produced the opposite effect (IC(50)= 239 +/- 68 nM). The inhibitory potency of octhilinone was selectively decreased by mutating cysteine 208 in MGL to glycine (IC(50); wild-type, 151 +/- 17 nM; C208G, 722 +/- 74 nM), but not by mutation of other cysteine residues (C32, C55, C201, C208 and C242).Conclusions and implicationsThe results indicated that cysteine 208 plays an important role in MGL function and identified a novel class of isothiazolinone-based MGL inhibitors with nanomolar potency in vitro.

The endogenous cannabinoid system plays an important role in the regulation of gastrointestinal function in health and disease. Endocannabinoid levels are regulated by catabolic enzymes. Here, we describe the presence and localization of monoacylglycerol lipase (MGL), the major enzyme responsible for the degradation of 2-arachidonoylglycerol. We used molecular, biochemical, immunohistochemical, and functional assays to characterize the distribution and activity of MGL. MGL mRNA was present in rat ileum throughout the wall of the gut. MGL protein was distributed in the muscle and mucosal layers of the ileum and in the duodenum, proximal colon, and distal colon. We observed MGL expression in nerve cell bodies and nerve fibers of the enteric nervous system. There was extensive colocalization of MGL with PGP 9.5 and calretinin-immunoreactive neurons, but not with nitric oxide synthase. MGL was also present in the epithelium and was highly expressed in the small intestine. Enzyme activity levels were highest in the duodenum and decreased along the gut with lowest levels in the distal colon. We observed both soluble and membrane-associated enzyme activities. The MGL inhibitor URB602 significantly inhibited whole gut transit in mice, an action that was abolished in cannabinoid 1 receptor-deficient mice. In conclusion, MGL is localized in the enteric nervous system where endocannabinoids regulate intestinal motility. MGL is highly expressed in the epithelium, where this enzyme may have digestive or other functions yet to be determined.

The N-aryl carbamate URB602 (biphenyl-3-ylcarbamic acid cyclohexyl ester) is an inhibitor of monoacylglycerol lipase (MGL), a serine hydrolase involved in the biological deactivation of the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG). Here, we investigated the mechanism by which URB602 inhibits purified recombinant rat MGL by using a combination of biochemical and structure-activity relationship (SAR) approaches. We found that URB602 weakly inhibits recombinant MGL (IC(50) = 223 +/- 63 microM) through a rapid and noncompetitive mechanism. Dialysis experiments and SAR analyses suggest that URB602 acts through a partially reversible mechanism rather than by irreversible carbamoylation of MGL. Finally, URB602 (100 microM) elevates 2-AG levels in hippocampal slice cultures without affecting levels of other endocannabinoid-related substances. Thus, URB602 may provide a useful tool by which to investigate the physiological roles of 2-AG and explore the potential interest of MGL as a therapeutic target.

Cyclooxygenase-2 (COX-2) can oxygenate the endocannabinoids, arachidonyl ethanolamide (AEA) and 2-arachidonylglycerol (2-AG), to prostaglandin-H2-ethanolamide (PGH2-EA) and -glycerol ester (PGH2-G), respectively. Further metabolism of PGH2-EA and PGH2-G by prostaglandin synthases produces a variety of prostaglandin-EA's and prostaglandin-G's nearly as diverse as those derived from arachidonic acid. Thus, COX-2 may regulate endocannabinoid levels in neurons during retrograde signaling or produce novel endocannabinoid metabolites for receptor activation. Endocannabinoid-metabolizing enzymes are important regulators of their action, so we tested whether PG-G levels may be regulated by monoacylglycerol lipase (MGL) and fatty acid amide hydrolase (FAAH). We found that PG-Gs are poor substrates for purified MGL and FAAH compared to 2-AG and/or AEA. Determination of substrate specificity demonstrates a 30-100- and 150-200-fold preference of MGL and FAAH for 2-AG over PG-Gs, respectively. The substrate specificity of AEA compared to those of PG-Gs was approximately 200-300 fold higher for FAAH. Thus, PG-Gs are poor substrates for the major endocannabinoid-degrading enzymes, MGL and FAAH.

Recent work in our laboratories has demonstrated that an opioid-independent form of stress-induced analgesia (SIA) is mediated by endogenous ligands for cannabinoid receptors-anandamide and 2-arachidonoylglycerol (2-AG) [A.G. Hohmann, R.L. Suplita, N.M. Bolton, M.H. Neely, D. Fegley, R. Mangieri, J.F. Krey, J.M. Walker, P.V. Holmes, J.D. Crystal, A. Duranti, A. Tontini, M. Mor, G. Tarzia, D. Piomelli, An endocannabinoid mechanism for stress-induced analgesia, Nature 435 (2005) 1108-1112]. The present study was conducted to examine the contribution of cannabinoid CB1 receptors in the basolateral nucleus of the amygdala (BLA) and central nucleus of the amygdala (CeA) to nonopioid SIA. SIA was induced by continuous footshock (3 min 0.9 mA) and quantified behaviorally using the tail-flick test. Microinjection of the CB1 antagonist/inverse agonist rimonabant (SR141716A) into the BLA, a limbic forebrain region with high densities of CB1 receptors, suppressed SIA relative to control conditions. By contrast, the same dose administered into the CeA, where CB1 immunoreactivity is largely absent, or outside the amygdala did not alter SIA. To examine the contribution of endocannabinoids in the BLA to SIA, we used selective pharmacological inhibitors of the anandamide-degrading enzyme fatty-acid amide hydrolase (FAAH) and the 2-arachidonoylglycerol-degrading enzyme monoacylglycerol lipase (MGL). The FAAH inhibitor URB597 and MGL inhibitor URB602, at doses that enhanced SIA following microinjection in the midbrain periaqueductal gray, did not alter SIA relative to control conditions. Our findings suggest that CB1 receptors in the BLA but not the CeA contribute to SIA, but pharmacological inhibition of endocannabinoid degradation at these sites does not affect the expression of stress antinociception.

The functions of 2-arachidonoylglycerol (2-AG), the most abundant endocannabinoid found in the brain, remain largely unknown. Here we show that two previously unknown inhibitors of monoacylglycerol lipase, a presynaptic enzyme that hydrolyzes 2-AG, increase 2-AG levels and enhance retrograde signaling from pyramidal neurons to GABAergic terminals in the hippocampus. These results establish a role for 2-AG in synaptic plasticity and point to monoacylglycerol lipase as a possible drug target.

Acute stress suppresses pain by activating brain pathways that engage opioid or non-opioid mechanisms. Here we show that an opioid-independent form of this phenomenon, termed stress-induced analgesia, is mediated by the release of endogenous marijuana-like (cannabinoid) compounds in the brain. Blockade of cannabinoid CB(1) receptors in the periaqueductal grey matter of the midbrain prevents non-opioid stress-induced analgesia. In this region, stress elicits the rapid formation of two endogenous cannabinoids, the lipids 2-arachidonoylglycerol (2-AG) and anandamide. A newly developed inhibitor of the 2-AG-deactivating enzyme, monoacylglycerol lipase, selectively increases 2-AG concentrations and, when injected into the periaqueductal grey matter, enhances stress-induced analgesia in a CB1-dependent manner. Inhibitors of the anandamide-deactivating enzyme fatty-acid amide hydrolase, which selectively elevate anandamide concentrations, exert similar effects. Our results indicate that the coordinated release of 2-AG and anandamide in the periaqueductal grey matter might mediate opioid-independent stress-induced analgesia. These studies also identify monoacylglycerol lipase as a previously unrecognized therapeutic target.

The endogenous cannabinoid 2-arachidonoylglycerol (2-AG) is produced by neurons and other cells in a stimulus-dependent manner and undergoes rapid biological inactivation through transport into cells and catalytic hydrolysis. The enzymatic pathways responsible for 2-AG degradation are only partially understood. We have shown previously that overexpression of monoacylglycerol lipase (MGL), a cytosolic serine hydrolase that cleaves 1- and 2-monoacylglycerols to fatty acid and glycerol, reduces stimulus-dependent 2-AG accumulation in primary cultures of rat brain neurons. We report here that RNA interference-mediated silencing of MGL expression greatly enhances 2-AG accumulation in HeLa cells. After stimulation with the calcium ionophore ionomycin, 2-AG levels in MGL-silenced cells were comparable with those found in cells in which 2-AG degradation had been blocked using methyl arachidonyl fluorophosphonate, a nonselective inhibitor of 2-AG hydrolysis. The results indicate that MGL plays an important role in the degradation of endogenous 2-AG in intact HeLa cells. Furthermore, immunodepletion experiments show that MGL accounts for at least 50% of the total 2-AG-hydrolyzing activity in soluble fractions of rat brain, suggesting that this enzyme also contributes to 2-AG deactivation in the central nervous system.

Fatty acid amide hydrolase (FAAH) and monoglyceride lipase (MGL) catalyse the hydrolysis of the endocannabinoids anandamide and 2-arachidonoyl glycerol. We investigated their ultrastructural distribution in brain areas where the localization and effects of cannabinoid receptor activation are known. In the hippocampus, FAAH was present in somata and dendrites of principal cells, but not in interneurons. It was located mostly on the membrane surface of intracellular organelles known to store Ca(2+) (e.g. mitochondria, smooth endoplasmic reticulum), less frequently on the somatic or dendritic plasma membrane. MGL immunoreactivity was found in axon terminals of granule cells, CA3 pyramidal cells and some interneurons. In the cerebellum, Purkinje cells and their dendrites are intensively immunoreactive for FAAH, together with a sparse axon plexus at the border of the Purkinje cell/granule cell layers. Immunostaining for MGL was complementary, the axons in the molecular layer were intensively labelled leaving the Purkinje cell dendrites blank. FAAH distribution in the amygdala was similar to that of the CB(1) cannabinoid receptor: evident signal in neuronal somata and proximal dendrites in the basolateral nucleus, and hardly any labelling in the central nucleus. MGL staining was restricted to axons in the neuropil, with similar relative signal intensities seen for FAAH in different nuclei. Thus, FAAH is primarily a postsynaptic enzyme, whereas MGL is presynaptic. FAAH is associated with membranes of cytoplasmic organelles. The differential compartmentalization of the two enzymes suggests that anandamide and 2-AG signalling may subserve functional roles that are spatially segregated at least at the stage of metabolism.

2-Arachidonoylglycerol (2-AG) is a naturally occurring monoglyceride that activates cannabinoid receptors and meets several key requisites of an endogenous cannabinoid substance. It is present in the brain (where its levels are 170-folds higher than those of anandamide), is produced by neurons in an activity- and calcium-dependent manner, and is rapidly eliminated. The mechanism of 2-AG inactivation is not completely understood, but is thought to involve carrier-mediated transport into cells followed by enzymatic hydrolysis. We examined the possible role of the serine hydrolase, monoglyceride lipase (MGL), in brain 2-AG inactivation. We identified by homology screening a cDNA sequence encoding for a 303-amino acid protein, which conferred MGL activity upon transfection to COS-7 cells. Northern blot and in situ hybridization analyses revealed that MGL mRNA is unevenly present in the rat brain, with highest levels in regions where CB1 cannabinoid receptors are also expressed (hippocampus, cortex, anterior thalamus and cerebellum). Immunohistochemical studies in the hippocampus showed that MGL distribution has striking laminar specificity, suggesting a presynaptic localization of the enzyme. Adenovirus-mediated transfer of MGL cDNA into rat cortical neurons increased the degradation of endogenously produced 2-AG in these cells, whereas no such effect was observed on anandamide degradation. These results indicate that hydrolysis via MGL may be a primary route of 2-AG inactivation in intact neuronal cells.

The endogenous cannabinoids (endocannabinoids) are lipid molecules that may mediate retrograde signaling at central synapses and other forms of short-range neuronal communication. The monoglyceride 2-arachidonoylglycerol (2-AG) meets several criteria of an endocannabinoid substance: (i) it activates cannabinoid receptors; (ii) it is produced by neurons in an activity-dependent manner; and (iii) it is rapidly eliminated. 2-AG inactivation is only partially understood, but it may occur by transport into cells and enzymatic hydrolysis. Here we tested the hypothesis that monoglyceride lipase (MGL), a serine hydrolase that converts monoglycerides to fatty acid and glycerol, participates in 2-AG inactivation. We cloned MGL by homology from a rat brain cDNA library. Its cDNA sequence encoded for a 303-aa protein with a calculated molecular weight of 33,367 daltons. Northern blot and in situ hybridization analyses revealed that MGL mRNA is heterogeneously expressed in the rat brain, with highest levels in regions where CB(1) cannabinoid receptors are also present (hippocampus, cortex, anterior thalamus, and cerebellum). Immunohistochemical studies in the hippocampus showed that MGL distribution has striking laminar specificity, suggesting a presynaptic localization of the enzyme. Adenovirus-mediated transfer of MGL cDNA into rat cortical neurons increased MGL expression and attenuated N-methyl-D-aspartate/carbachol-induced 2-AG accumulation in these cells. No such effect was observed on the accumulation of anandamide, another endocannabinoid lipid. The results suggest that hydrolysis by means of MGL is a primary mechanism for 2-AG inactivation in intact neurons.

New potent, selective monoacylglycerol lipase (MAGL) inhibitors based on the azetidin-2-one scaffold ((±)- 5a - v , (±)- 6a - j , and (±)- 7a - d ) were developed as irreversible ligands, as demonstrated by enzymatic and crystallographic studies for (±)- 5d , (±)- 5l , and (±)- 5r . X-ray analyses combined with extensive computational studies allowed us to clarify the binding mode of the compounds. 5v was identified as selective for MAGL when compared with other serine hydrolases. Solubility, in vitro metabolic stability, cytotoxicity, and absence of mutagenicity were determined for selected analogues. The most promising compounds ((±)- 5c , (±)- 5d , and (±)- 5v ) were used for in vivo studies in mice, showing a decrease in MAGL activity and increased 2-arachidonoyl- sn -glycerol levels in forebrain tissue. In particular, 5v is characterized by a high eudysmic ratio and (3 R ,4 S )- 5v is one of the most potent irreversible inhibitors of h / m MAGL identified thus far. These results suggest that the new MAGL inhibitors have therapeutic potential for different central and peripheral pathologies.

Rationale: Renal fibrosis, with no therapeutic approaches, is a common pathological feature in various chronic kidney diseases (CKD). Tubular cell injury plays a pivotal role in renal fibrosis. Commonly, injured tubular cells exhibit significant lipid accumulation. However, the underlying mechanisms remain poorly understood. Methods: 2-arachidonoylglycerol (2-AG) levels in CKD patients and CKD model specimens were measured using mass spectrometry. 2-AG-loaded nanoparticles were infused into unilateral ureteral obstruction (UUO) mice. Lipid accumulation and renal fibrosis were tested. Furthermore, monoacylglycerol lipase (MAGL), the hydrolyzing enzyme of 2-AG, was assessed in CKD patients and models. Tubular cell-specific MAGL knock-in mice were generated. Moreover, MAGL recombination protein was also administered to unilateral ischemia reperfusion injury (UIRI) mice. Besides, a series of methods including RNA sequencing, metabolomics, primary cell culture, lipid staining, etc. were used. Results: 2-AG was increased in the serum or kidneys from CKD patients and models. Supplement of 2-AG further induced lipid accumulation and fibrogenesis through cannabinoid receptor type 2 (CB2)/β-catenin signaling. β-catenin knockout blocked 2-AG/CB2-induced fatty acid β-oxidation (FAO) deficiency and lipid accumulation. Remarkably, MAGL significantly decreased in CKD, aligning with lipid accumulation and fibrosis. Specific transgene of MAGL in tubular cells significantly preserved FAO, inhibited lipid-mediated toxicity in tubular cells, and finally retarded fibrogenesis. Additionally, supplementation of MAGL in UIRI mice also preserved FAO function, inhibited lipid accumulation, and protected against renal fibrosis. Conclusion: MAGL is a potential diagnostic marker for kidney function decline, and also serves as a new therapeutic target for renal fibrosis through ameliorating lipotoxicity., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Tumor metastasis is a spatial and temporal process that starts with remodeling to generate a proper premetastatic niche in a distant tissue. Infiltration of immunosuppressive macrophages is one of the notable characteristics in the premetastatic niche, which is a fundamental requirement for primary tumor metastasis. Here, we demonstrated that small extracellular vesicles (sEV) carrying RAB21 homed to lung macrophages and interacted with integrin-β1 on macrophages. ABHD12 expression was high in lung metastatic tumors and was mostly expressed by macrophages. Head and neck squamous cell carcinoma (HNSCC)-derived sEVs carrying ABHD12-polarized macrophages toward an immunosuppressive phenotype, driving premetastatic niche formation, which facilitated lung metastasis. ABHD12 additionally upregulated S1PR1 by activating the AKT-FoxO1 pathway in macrophages, and significantly enhanced antitumor responses were observed in tumor models treated with agents targeting both S1PR1 and PD-1. Collectively, our study suggests that RAB21+ABHD12+ sEVs derived from HNSCC cells contribute to the formation of the immunosuppressive microenvironment in the premetastatic niche and are a potential therapeutic target for enhancing the antitumor efficacy of anti-PD-1 therapy., (©2024 American Association for Cancer Research.)

The mechanisms of β -caryophyllene (BCP)-induced analgesia are not well studied. Here, we tested the efficacy of BCP in an acute postsurgical pain model and evaluated its effect on the endocannabinoid system. Rats were treated with vehicle and 10, 25, 50, and 75 mg/kg BCP. Paw withdrawal responses to mechanical stimuli were evaluated using an electronic von Frey anesthesiometer. Endocannabinoids, including 2-arachidonoylglycerol (2-AG), were also evaluated in plasma and tissues using high-performance liquid chromatography-tandem mass spectrometry. Monoacylglycerol lipase (MAGL) activity was evaluated in vitro as well as ex vivo. We observed a dose-dependent and time-dependent alleviation of hyperalgesia in incised paws up to 85% of the baseline value at 30 minutes after administration of BCP. We also observed dose-dependent increases in the 2-AG levels of about threefold after administration of BCP as compared with vehicle controls. Incubations of spinal cord tissue homogenates from BCP-treated rats with isotope-labeled 2-arachidonoylglycerol-d8 revealed a reduced formation of the isotope-labeled MAGL product 2-AG-d8 as compared with vehicle controls, indicating MAGL enzyme inhibition. In vitro MAGL enzyme activity assessment using 2-AG as the substrate revealed an IC 50 of 15.8 µM for MAGL inhibition using BCP. These data showed that BCP inhibits MAGL activity in vitro and in vivo, causing 2-AG levels to rise. Since the endocannabinoid 2-AG is a CB1 and CB2 receptor agonist, we propose that 2-AG-mediated cannabinoid receptor activation contributes to BCP's mechanism of analgesia. SIGNIFICANCE STATEMENT: β -Caryophyllene (BCP) consumption is relatively safe and is approved by the Food and Drug Administration as a flavoring agent, which can be used in cosmetic and food additives. BCP is a potent anti-inflammatory agent that showed substantial antihyperalgesic properties in this study of acute pain suggesting that BCP might be an alternative to opioids. This study shows an additive mechanism (monoacylglycerol lipase inhibition) by which BCP might indirectly alter CB1 and CB2 receptor activity and exhibit its pharmacological properties., (Copyright © 2024 by The Author(s).)

S-palmitoylases and S-depalmitoylases are differentially expressed in various cancers and several malignant tumors and show a strong prognostic ability. Notwithstanding, the potential clinical impact of S-palmitoylases and S-depalmitoylases, particularly in the prognosis and progression of lung adenocarcinoma (LUAD), has not been clarified. Expression levels of S-palmitoylases and S-depalmitoylases in LUAD were investigated using TCGA. GEPIA was used to evaluate the mRNA levels of S-palmitoylases and S-depalmitoylases at different pathological stages. Metascape was used to investigate the biological significance of S-palmitoylases and S-depalmitoylases. The Kaplan-Meier plotter was used to analyze the prognostic value of S-palmitoylases and S-depalmitoylases. CBioportal was used to analyze gene alterations in S-palmitoylases and S-depalmitoylases. UALCAN was used to examine DNA promoter methylation levels of S-palmitoylases and S-depalmitoylases. Finally, we investigated the relationship between S-palmitoylases, S-depalmitoylases, and tumor-infiltrating immune cells using TIMER. Correlations with immune checkpoint-related genes were determined using the R packages reshape2, ggpubr, ggplot2, and corrplot. PCR was also performed to assess the degree of ZDHHC4/12/18/24 and APT2 transcript expression in lung adenocarcinoma and adjacent normal lung tissues. HPA was utilized to investigate protein levels of S-palmitoylases and S-depalmitoylases in LUAD and normal lung tissue. Our study found that ZDHHC2/3/4/5/6/7/9/12/13/16/18/20/21/23/24, APT1/2, PPT1, LYPLAL1, ABHD4/10/11/12/13 and ABHD17C mRNA expression was significantly upregulated in LUAD, whereas ZDHHC1/8/11/11B/14/15/17/19/22, ABHD6/16A and ABHD17A mRNA expression was significantly downregulated. The functions of the differentially expressed S-palmitoylases and S-depalmitoylases were mainly associated with protein-cysteine S-palmitoyltransferase and protein-cysteine S-acyltransferase activities. Patients with high expression of ZDHHC4/12/18/24, APT2, ABHD4, ABHD11 and ABHD12 had a shorter overall survival. Infiltration of six immune cells (B cells, CD8 + T cells, CD4 + T cells, macrophages, neutrophils, and dendritic cells) was closely associated with the expression of ZDHHC4/12/18/24 and APT2. ZDHHC4/12/18/24 and APT2 positively correlated with the immune checkpoint-related gene CD276. We assessed the mRNA levels of ZDHHC4/12/18/24 and APT2 using qRT-PCR and found increased expression of ZDHHC4/12/18/24 in LUAD compared with healty control lung tissues. ZDHHC4/12/18/24, and APT2 are potential prognostic biomarkers of LUAD. Their expression levels could be related to the tumor microenvironment in LUAD., (© 2024. The Author(s).)

Monoacylglycerol lipase (MAGL) regulates endocannabinoid 2-arachidonoylglycerol (2-AG) and eicosanoid signalling. MAGL inhibition provides therapeutic opportunities but clinical potential is limited by central nervous system (CNS)-mediated side effects. Here, we report the discovery of LEI-515, a peripherally restricted, reversible MAGL inhibitor, using high throughput screening and a medicinal chemistry programme. LEI-515 increased 2-AG levels in peripheral organs, but not mouse brain. LEI-515 attenuated liver necrosis, oxidative stress and inflammation in a CCl 4 -induced acute liver injury model. LEI-515 suppressed chemotherapy-induced neuropathic nociception in mice without inducing cardinal signs of CB 1 activation. Antinociceptive efficacy of LEI-515 was blocked by CB 2 , but not CB 1 , antagonists. The CB 1 antagonist rimonabant precipitated signs of physical dependence in mice treated chronically with a global MAGL inhibitor (JZL184), and an orthosteric cannabinoid agonist (WIN55,212-2), but not with LEI-515. Our data support targeting peripheral MAGL as a promising therapeutic strategy for developing safe and effective anti-inflammatory and analgesic agents., (© 2023. The Author(s).)

Background and Purpose: The endocannabinoid (eCB) system plays an important homeostatic role in the regulation of stress circuits and has emerged as a therapeutic target to treat stress disorders and alcohol use disorder (AUD). Extensive research has elucidated a role for the eCB anandamide (AEA), but less is known about 2-arachidonoylglycerol (2-AG) mediated signalling., Experimental Approach: We pharmacologically enhanced eCB signalling by inhibiting the 2-AG metabolizing enzyme, monoacylglycerol lipase (MAGL), in male and female Marchigian Sardinian alcohol-preferring (msP) rats, a model of innate alcohol preference and stress hypersensitivity, and in control Wistar rats. We tested the acute effect of the selective MAGL inhibitor MJN110 in alleviating symptoms of alcohol drinking, anxiety, irritability and fear., Key Results: A single systemic administration of MJN110 increased 2-AG levels in the central amygdala, prelimbic and infralimbic cortex but did not acutely alter alcohol drinking. MAGL inhibition reduced aggressive behaviours in female msPs, and increased defensive behaviours in male msPs, during the irritability test. Moreover, in the novelty-induced hypophagia test, MJN110 selectively enhanced palatable food consumption in females, mitigating stress-induced food suppression. Lastly, msP rats showed increased conditioned fear behaviour compared with Wistar rats, and MJN110 reduced context-associated conditioned fear responses, but not cue-probed fear expression, in male msPs., Conclusions and Implications: Acute inhibition of MAGL attenuated some stress-related responses in msP rats but not voluntary alcohol drinking. Our results provide new insights into the sex dimorphism documented in stress-induced responses. Sex-specific eCB-based approaches should be considered in the clinical development of therapeutics., (© 2023 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Ｏｂｊｅｃｔｉｖｅ Ｔｏ ｉｎｖｅｓｔｉｇａｔｅ ｔｈｅ ｒｏｌｅ ａｎｄ ｍｅｃｈａｎｉｓｍ ｏｆ ａｃｔｉｏｎ ｏｆ ｍｏｎｏａｃｙｌｇｌｙｃｅｒｏｌ ｌｉｐａｓｅ （ＭＡＧＬ）ｏｎ ｔｈｅ ｇｒｏｗｔｈ ｏｆ ｎｕｄｅ ｍｉｃｅ ｘｅｎ ｏｇｒａｆｔ ｔｕｍｏｒ ｏｆ ｈｕｍａｎ ｈｅｐａｔｏｃｅｌｌｕｌａｒ ｃａｒｃｉｎｏｍａ （ＨＣＣ）． Ｍｅｔｈｏｄｓ Ｔｈｅ ｔｒａｎｓｐｌａｎｔｅｄ ＳＭＭＣ －７７２１ ｃｅｌｌｓ ｗｅｒｅ ｄｉｖｉｄｅｄ ｉｎｔｏ ＳＭＭＣ －７７２１ＷＴ ｇｒｏｕｐ （ｗｉｔｈｏｕｔ ｔｒｅａｔｍｅｎｔ），ＳＭＭＣ －７７２１ＭＡＧＬ － ＫＤ ｇｒｏｕｐ （ｗｉｔｈ ＭＡＧＬ ｓｉｌｅｎｃｉｎｇ），ＳＭＭＣ － ７７２１ＭＡＧＬ － ＯＥ ｇｒｏｕｐ （ｗｉｔｈ ＭＡＧＬ ｏｖｅｒｅｘｐｒｅｓ ｓｉｏｎ），ａｎｄ ＳＭＭＣ －７７２１Ｖｅｃｔｏｒ ｇｒｏｕｐ （ｔｒａｎｓｆｅｃｔｅｄ ｗｉｔｈ ｅｍｐｔｙ ｖｅｃｔｏｒ）． Ａ ｔｏｔａｌ ｏｆ ２７ ｍａｌｅ ＢＡＬＢ／ ｃ ｎｕｄｅ ｍｉｃｅ ｗｅｒｅ ｒａｎｄｏｍｌｙ ｄｉｖｉｄｅｄ ｉｎｔｏ ｇｒｏｕｐ Ａ （１２ ｍｉｃｅ ｉｎｊｅｃｔｅｄ ｗｉｔｈ ｔｈｅ ｃｅｌｌｓ ｉｎ ｔｈｅ ＳＭＭＣ － ７７２１ＷＴ ｇｒｏｕｐ），ｇｒｏｕｐ Ｂ （５ ｍｉｃｅ ｉｎｊｅｃｔｅｄ ｗｉｔｈ ｔｈｅ ｃｅｌｌｓ ｉｎ ｔｈｅ ＳＭＭＣ － ７７２１ＭＡＧＬ － ＫＤ ｇｒｏｕｐ），ｇｒｏｕｐ Ｃ （５ ｍｉｃｅ ｉｎｊｅｃｔｅｄ ｗｉｔｈ ｔｈｅ ｃｅｌｌｓ ｉｎ ｔｈｅ ＳＭＭＣ －７７２１ＭＡＧＬ － ＯＥ ｇｒｏｕｐ），ａｎｄ ｇｒｏｕｐ Ｄ （５ ｍｉｃｅ ｉｎｊｅｃｔｅｄ ｗｉｔｈ ｔｈｅ ｃｅｌｌｓ ｉｎ ｔｈｅ ＳＭＭＣ －７７２１Ｖｅｃｔｏｒ ｇｒｏｕｐ）． Ｔｈｅ ｍｉｃｅ ｉｎ ｇｒｏｕｐ Ａ ｗｅｒｅ ｆｕｒｔｈｅｒ ｄｉｖｉｄｅｄ ｉｎｔｏ ｇｒｏｕｐｓ Ａ１ （ｃｏｎｔｒｏｌ ｇｒｏｕｐ），Ａ２ （ｔｒｅａｔｅｄ ｗｉｔｈ ｈｉｇｈ － ｆａｔ ｄｉｅｔ ａｎｄ ＪＺＬ１８４，ａ ｓｐｅｃｉｆｉｃ ｉｎｈｉｂｉｔｏｒ ｏｆ ＭＡＧＬ），ａｎｄ Ａ３ （ｆｅｄ ｗｉｔｈ ｈｉｇｈ － ｆａｔ ｄｉｅｔ），ｗｉｔｈ ４ ｍｉｃｅ ｉｎ ｅａｃｈ ｇｒｏｕｐ． Ｔｈｅ ｆｏｕｒ ｇｒｏｕｐｓ ｗｅｒｅ ｃｏｍｐａｒｅｄ ｉｎ ｔｅｒｍｓ ｏｆ ｔｈｅ ｃｈａｎｇｅ ｉｎ ｔｕｍｏｒ ｖｏｌｕｍｅ ａｎｄ ｔｈｅ ｅｘｐｒｅｓｓｉｏｎ ｏｆ ｐｒｏｌｉｆｅｒａｔｉｎｇ ｃｅｌｌ ｎｕｃｌｅａｒ ａｎｔｉｇｅｎ （ＰＣＮＡ），ｍｅｔａｌ ｍａｔｒｉｘ ｐｒｏｔｅｉｎａｓｅ －２ （ＭＭＰ －２），ｌｙｓｏｐｈｏｓｐｈａｔｉｄｉｃ ａｃｉｄ （ＬＰＡ），ａｎｄ ｐｒｏｓｔａｇｌａｎｄｉｎ Ｅ２ （ＰＧＥ２）ｉｎ ｔｕｍｏｒ． Ａ ｏｎｅ － ｗａｙ ａｎａｌｙｓｉｓ ｏｆ ｖａｒｉａｎｃｅ ｗａｓ ｕｓｅｄ ｆｏｒ ｃｏｍｐａｒｉ ｓｏｎ ｏｆ ｃｏｎｔｉｎｕｏｕｓ ｄａｔａ ｂｅｔｗｅｅｎ ｍｕｌｔｉｐｌｅ ｇｒｏｕｐｓ，ａｎｄ ｔｈｅ ＳＮＫ － ｑ ｔｅｓｔ ｗａｓ ｕｓｅｄ ｆｏｒ ｆｕｒｔｈｅｒ ｃｏｍｐａｒｉｓｏｎ ｂｅｔｗｅｅｎ ｔｗｏ ｇｒｏｕｐｓ． Ｒｅｓｕｌｔｓ Ｔｈｅｒｅ ｗａｓ ａ ｓｉｇｎｉｆｉｃａｎｔ ｄｉｆｆｅｒｅｎｃｅ ｉｎ ｔｈｅ ｒｅｌａｔｉｖｅ ｐｒｏｔｅｉｎ ｅｘｐｒｅｓｓｉｏｎ ｏｆ ＭＡＧＬ ｂｅｔｗｅｅｎ ｔｈｅ ＳＭＭＣ － ７７２１ＷＴ ｇｒｏｕｐ，ｔｈｅ ＳＭＭＣ － ７７２１ＭＡＧＬ － ＫＤ ｇｒｏｕｐ，ａｎｄ ｔｈｅ ＳＭＭＣ －７７２１ＭＡＧＬ － ＯＥ ｇｒｏｕｐ （０． ３７７ ±０． ０２６ ｖｓ ０． １８２ ± ０． ０５５ ｖｓ ０． ６８９ ± ０． ０１９，Ｆ ＝ ３３． ３８２，Ｐ ＜ ０． ００１）；ｃｏｍｐａｒｅｄ ｗｉｔｈ ｔｈｅ ＳＭＭＣ － ７７２１ＷＴ ｇｒｏｕｐ，ｔｈｅ ＳＭＭＣ － ７７２１ＭＡＧＬ － ＫＤ ｇｒｏｕｐ ｈａｄ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｌｏｗｅｒ ｐｒｏｔｅｉｎ ｅｘｐｒｅｓｓｉｏｎ ｏｆ ＭＡＧＬ ａｎｄ ｔｈｅ ＳＭＭＣ － ７７２１ＭＡＧＬ － ＯＥ ｇｒｏｕｐ ｈａｄ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｅｘｐｒｅｓｓｉｏｎ （Ｐ ＜０． ０５）． Ｔｈｅｒｅ ｗａｓ ａ ｓｉｇｎｉｆｉｃａｎｔ ｄｉｆｆｅｒｅｎｃｅ ｉｎ ｔｈｅ ｓｉｚｅ ｏｆ ｓｕｂｃｕｔａｎｅｏｕｓ ｘｅｎｏｇｒａｆｔ ｔｕｍｏｒ ｂｅｔｗｅｅｎ ｇｒｏｕｐｓ Ａ，Ｂ，Ｃ，ａｎｄ Ｄ （４２３６． １２５ ± １２８４． ２８３ ｍｍ３ ｖｓ １８８３． ３７５ ± ５５２． ９７７ ｍｍ３ ｖｓ １０ １４６． ０６１ ± １８４２． ２６４ ｍｍ３ ｖｓ ４３０７ ４５２ ±２０７０． ７０８ ｍｍ３，Ｆ ＝６． ８０４，Ｐ ＝０． ０２３）． Ｇｒｏｕｐ Ｃ ｈａｄ ａ ｌｏｗｅｒ ｇｒｏｗｔｈ ｒａｔｅ ｏｆ ｓｕｂｃｕｔａｎｅｏｕｓ ｘｅｎｏｇｒａｆｔ ｔｕｍｏｒ ｔｈａｎ ｇｒｏｕｐ Ａ （Ｐ ＜ ０ ０５），ａｎｄ ｇｒｏｕｐ Ｂ ｈａｄ ａ ｈｉｇｈｅｒ ｇｒｏｗｔｈ ｒａｔｅ ｔｈａｎ ｇｒｏｕｐ Ａ （Ｐ ＜０． ０５）． Ｔｈｅｒｅ ｗｅｒｅ ｓｉｇｎｉｆｉｃａｎｔ ｄｉｆｆｅｒｅｎｃｅｓ ｂｅｔｗｅｅｎ ｇｒｏｕｐｓ Ａ，Ｂ，ａｎｄ Ｃ ｉｎ ｔｈｅ ｌｅｖｅｌｓ ｏｆ ＰＣＮＡ （２５ ８４３． ８２１ ±４２０１． ３１０ ｖｓ １７ ４２６． ９５ ±５１３９． ２０２ ｖｓ ３９ ７５３． １０３ ±５７２１． ４４４，Ｆ ＝２１． ４８２，Ｐ ＜０． ００１）ａｎｄ ＭＭＰ －２ （５２ ８４１． ６２１ ±４３３９． ２５３ ｖｓ ３５ ５１１． ４５１ ±８２５１． ４２３ ｖｓ ６８ ２７４． ７３１ ±６４１８． ５９４，Ｆ ＝１１． ５２６，Ｐ ＜０． ００１）；ｇｒｏｕｐ Ｂ ｈａｄ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｌｏｗｅｒ ｌｅｖｅｌｓ ｏｆ ＰＣＮＡ ａｎｄ ＭＭＰ －２ ｔｈａｎ ｇｒｏｕｐ Ａ （Ｐ ＜０． ０５），ａｎｄ ｇｒｏｕｐ Ｃ ｈａｄ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｌｅｖｅｌｓ ｔｈａｎ ｇｒｏｕｐ Ａ （Ｐ ＜０． ０５）． Ｔｈｅｒｅ ｗａｓ ａ ｓｉｇｎｉｆｉｃａｎｔ ｄｉｆｆｅｒｅｎｃｅ ｉｎ ｔｕｍｏｒ ｖｏｌｕｍｅ ｂｅｔｗｅｅｎ ｇｒｏｕｐｓ Ａ１，Ａ２，ａｎｄ Ａ３ （２３ ４７６． ２８９ ± ４８３． ８７２ ｍｍ３ ｖｓ １８ ５９３． ８５１ ± １３８５． ８０５ ｍｍ３ ｖｓ ３７ ７０３． １９８ ±２９２５． ２５４ ｍｍ３，Ｆ ＝４７． ３７１，Ｐ ＝０． ００４）． Ｃｏｍｐａｒｅｄ ｗｉｔｈ ｇｒｏｕｐ Ａ１，ｇｒｏｕｐ Ａ３ ｈａｄ ａ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｇｒｏｗｔｈ ｒａｔｅ ｏｆ ｓｕｂ ｃｕｔａｎｅｏｕｓ ｘｅｎｏｇｒａｆｔ ｔｕｍｏｒ （Ｐ ＜０． ０５）ａｎｄ ｇｒｏｕｐ Ａ２ ｈａｄ ａ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｌｏｗｅｒ ｇｒｏｗｔｈ ｒａｔｅ （Ｐ ＜０． ０５）． Ｔｈｅｒｅ ｗａｓ ａ ｓｉｇｎｉｆｉｃａｎｔ ｄｉｆｆｅｒｅｎｃｅ ｉｎ ｔｈｅ ｌｅｖｅｌ ｏｆ ＰＧＥ２ ｂｅｔｗｅｅｎ ｇｒｏｕｐｓ Ａ１，Ａ２，ａｎｄ Ａ３ （０． １０９ ± ０． ０２３ μｍｏｌ／ Ｌ ｖｓ ０． ０５６ ± ０． ０１０ μｍｏｌ／ Ｌ ｖｓ ０． １６８ ± ０． ０２４ μｍｏｌ／ Ｌ，Ｆ ＝ １６ ４９２，Ｐ ＜０． ００１）；ｇｒｏｕｐ Ａ３ ｈａｄ ａ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｌｅｖｅｌ ｏｆ ＰＧＥ２ ｔｈａｎ ｇｒｏｕｐ Ａ１ （Ｐ ＜０． ０５），ａｎｄ ｇｒｏｕｐ Ａ２ ｈａｄ ａ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｌｏｗｅｒ ｌｅｖｅｌ ｔｈａｎ ｇｒｏｕｐ Ａ１ （Ｐ ＜０． ０５）． Ｔｈｅｒｅ ｗａｓ ａ ｓｉｇｎｉｆｉｃａｎｔ ｄｉｆｆｅｒｅｎｃｅ ｉｎ ｔｈｅ ｌｅｖｅｌ ｏｆ ＰＧＥ２ ｂｅｔｗｅｅｎ ｇｒｏｕｐｓ Ｂ，Ｃ，ａｎｄ Ｄ （０． ０６９ ± ０． ０２５ μｍｏｌ／ Ｌ ｖｓ ０． １７５ ±０． ０２３ μｍｏｌ／ Ｌ ｖｓ ０． ０９６ ±０． ０１９ μｍｏｌ／ Ｌ，Ｆ ＝３１． ５５０，Ｐ ＜ ０． ００１）；ｇｒｏｕｐ Ｂ ｈａｄ ａ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｌｏｗｅｒ ｌｅｖｅｌ ｏｆ ＰＧＥ２ ｔｈａｎ ｇｒｏｕｐ Ｄ （Ｐ ＜０． ０５），ａｎｄ ｇｒｏｕｐ Ｃ ｈａｄ ａ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｌｅｖｅｌ ｔｈａｎ ｇｒｏｕｐ Ｄ （Ｐ ＜ ０． ０５）． Ｃｏｎｃｌｕｓｉｏｎ ＭＡＧＬ ｃａｎ ｐｒｏｍｏｔｅ ｔｈｅ ｇｒｏｗｔｈ ｏｆ ｓｕｂｃｕｔａｎｅｏｕｓ ｘｅｎｏｇｒａｆｔ ｔｕｍｏｒ ｏｆ ＨＣＣ ｂｙ ｒｅｇｕｌａｔｉｎｇ ＰＧＥ２，ｓｕｇｇｅｓｔｉｎｇ ｔｈａｔ ＭＡＧＬ ｍｉｇｈｔ ｂｅｃｏｍｅ ａ ｐｏｔｅｎｔｉａｌ ｔａｒｇｅｔ ｆｏｒ ＨＣＣ ｔｒｅａｔ ｍｅｎｔ ｉｎ ｆｕｔｕｒｅ． [ABSTRACT FROM AUTHOR]