Fatty Acid Amide Hydrolase Inhibitor Research Articles

FAAH Inhibition Counteracts Neuroinflammation via Autophagy Recovery in AD Models

Endocannabinoids have attracted great interest for their ability to counteract the neuroinflammation underlying Alzheimer’s disease (AD). Our study aimed at evaluating whether this activity was also due to a rebalance of autophagic mechanisms in cellular and animal models of AD. We supplied URB597, an inhibitor of Fatty-Acid Amide Hydrolase (FAAH), the degradation enzyme of anandamide, to microglial cultures treated with Aβ25-35, and to Tg2576 transgenic mice, thus increasing the endocannabinoid tone. The addition of URB597 did not alter cell viability and induced microglia polarization toward an anti-inflammatory phenotype, as shown by the modulation of pro- and anti-inflammatory cytokines, as well as M1 and M2 markers; moreover microglia, after URB597 treatment released higher levels of Bdnf and Nrf2, confirming the protective role underlying endocannabinoids increase, as shown by RT-PCR and immunofluorescence experiments. We assessed the number and area of amyloid plaques in animals administered with URB597 compared to untreated animals and the expression of autophagy key markers in the hippocampus and prefrontal cortex from both groups of mice, via immunohistochemistry and ELISA. After URB597 supply, we detected a reduction in the number and areas of amyloid plaques, as detected by Congo Red staining and a reshaping of microglia activation as shown by M1 and M2 markers’ modulation. URB597 administration restored autophagy in Tg2576 mice via an increase in BECN1 (Beclin1), ATG7 (Autophagy Related 7), LC3 (light chain 3) and SQSTM1/p62 (sequestrome 1) as well as via the activation of the ULK1 (Unc-51 Like Autophagy Activating Kinase 1) signaling pathway, suggesting that it targets mTOR/ULK1-dependent autophagy pathway. The potential of endocannabinoids to rebalance autophagy machinery may be considered as a new perspective for therapeutic intervention in AD.

Natural phenol carbamates: Selective BuChE/FAAH dual inhibitors show neuroprotection in an Alzheimer's disease mouse model

FAAH inhibition can indirectly enhance endocannabinoid signaling to therapeutic levels, effectively preventing or slowing its progression of Alzheimer's disease (AD). Hence, the search for effective dual FAAH/cholinesterase inhibitors is considerable need for disease-modifying therapies. To this aim, we designed, synthesized, and tested three series of natural phenol carbamates. The majority of carbamates proved to be potent on a single target, amongst them, compound D12 containing paeonol motif was identified as an effective dual BuChE/FAAH inhibitor, with well-balanced nanomolar activity (IC50 = 81 and 400 nM for hBuChE and hFFAH, respectively). D12 possessed BBB penetrating ability, benign safety, neuroprotection and pseudo-irreversible BuChE inhibition (Kd = 2.11 μM, k2 = 2.27 min−1), showing good drug-like properties. D12 also modulated the BV2 microglial polarization to inhibit neuroinflammation. In vivo study verified that D12 improved Aβ1-41-induced learning impairments in AD mouse model for both short- and long-term memory responses. Thus, the dual activity of D12 could lead to a potentially more effective treatment for the counteraction of AD progression.

Efficacy and safety of JNJ-42165279, a fatty acid amide hydrolase inhibitor, in adolescents and adults with autism spectrum disorder: a randomized, phase 2, placebo-controlled study.

JNJ-42165279, a highly selective and orally bioavailable fatty acid amide (FAA) hydrolase inhibitor, was evaluated for efficacy and safety in adolescents and adults with autism spectrum disorder (ASD) in this phase 2, double-blind, placebo-controlled, multicenter study (NCT03664232). Participants aged 13-35 years, with a diagnosis of ASD (Diagnostic and Statistical Manual of Mental Disorders, 5th edition; Autism Diagnostic Observation Schedule, 2nd edition) were randomized (1:1) to 12 weeks of treatment with JNJ-42165279 (25 mg, twice-daily) or placebo. Primary endpoints were the change in the Autism Behavior Inventory (ABI) Core Domain (ABI-CD), ABI-Social Communication (ABI-SC), and ABI-Repetitive/Restrictive Behavior (ABI-RB) scores from baseline to day 85. Of the 61 participants (16 female, 45 male) included in the efficacy analyses, 53 (87%) completed the double-blind treatment. At day 85, the JNJ-42165279 group did not show a statistically significant reduction in ASD symptoms versus placebo, as assessed with ABI-CD (p = 0.284), ABI-SC (p = 0.290), and ABI-RB (p = 0.231). However, the following secondary outcomes exhibited small to moderate changes directionally favoring JNJ-42165279: Social Responsiveness Scale 2 (SRS, p = 0.064), Repetitive Behavior Scale-Revised (RBS-R, p = 0.006), Zarit Burden Interview short version (ZBI, p = 0.063), Child Adolescent Symptom Inventory-Anxiety (CASI-Anx, p = 0.048), and Caregiver Global Impression of Severity (p = 0.075). Notably, versus placebo, JNJ-42165279-treated participants showed increased concentrations of FAAs throughout the treatment period, with those achieving elevated concentrations experiencing the greatest reduction in the SRS total score at day 85. JNJ-42165279 demonstrated an acceptable safety profile. Although primary endpoints were not met, JNJ-42165279 may have a therapeutic effect on certain aspects of core ASD symptoms.

FAAH inhibitor URB597 shows anti-hyperalgesic action and increases brain and intestinal tissues fatty acid amides in a model of CRF1 agonist mediated visceral hypersensitivity in male rats.

The endocannabinoid (eCB) system includes ligands (anandamide and 2-arachidonoyl glycerol, 2-AG), receptors and catabolizing enzymes (fatty acid amide hydrolase, FAAH and monoacylglycerol lipase) expressed in both the brain and gut. We investigated whether the FAAH inhibitor, URB597, influenced visceral pain to colorectal distension (CRD) in an acute stress-related model of visceral hypersensitivity induced by the selective corticotropin-releasing factor receptor subtype 1 (CRF1) agonist, cortagine. Male Sprague-Dawley rats were injected subcutaneously (SC) with URB597 (3 mg/kg) or vehicle and 2 h later, intraperitoneally with cortagine (10 μg/kg) or vehicle. The visceromotor responses (VMR) were assessed to a first CRD (baseline) before injections, and to a second CRD 15 min after the last treatment. Brain, jejunum, and proximal colon were collected from treated and naïve rats for levels quantification of three fatty acid amides (FAAs) [anandamide (arachidonyl-ethanolamide, AEA), oleoyl-ethanolamide (OEA) and palmitoyl-ethanolamide (PEA)], and 2-AG. In separate animals, defecation/diarrhea were monitored after URB597 and cortagine. URB597 inhibited cortagine-induced increased VMR at 40 mmHg (89.0 ± 14.8% vs. 132.5 ± 15.6% for vehicle SC, p < 0.05) and 60 mmHg (107.5 ± 16.1% vs. 176.9 ± 24.4% for vehicle SC, p < 0.001) while not influencing basal VMR. In URB597 plus cortagine group, FAAs levels increased in the brain and intestinal tissue while 2-AG did not change. URB597 did not modify cortagine-induced defecation/diarrhea versus vehicle. URB597 shows efficacy to elevate brain and intestinal FAAs and to counteract the colonic hypersensitivity induced by peripheral activation of CRF1 signaling supporting a potential strategy of FAAH inhibitors to alleviate stress-related visceral hypersensitivity.

Mitigation of cisplatin-induced acute kidney injury through oral administration of FAAH Inhibitor PF-04457845.

Fatty acid amide hydrolase (FAAH) serves as the primary enzyme responsible for degrading the endocannabinoid anandamide (AEA). Inhibition of FAAH, either through pharmacological means or genetic manipulation, can effectively reduce inflammation in various organs, including the brain, colon, heart, and kidneys. Infusion of a FAAH inhibitor into the kidney medulla has been shown to induce diuretic and natriuretic effects. FAAH knockout mice have shown protection against both post-ischemia reperfusion injury and cisplatin-induced acute kidney injury (AKI), although through distinct mechanisms. The present study was based on the hypothesis that pharmacological inhibition of FAAH activity could mitigate cisplatin-induced AKI, exploring potential renoprotective mechanism. Male wild type C57BL/6 were administered an oral gavage of a FAAH inhibitor (PF-04457845, 5mg/kg) or vehicle (10% PEG200+5% Tween80+normal saline) at 72, 48, 24, and 2 hours before and 24 and 48 hours after a single intraperitoneal injection of cisplatin (Cis, 25 mg/kg). Mice were euthanatized 72 hours after cisplatin treatment. Compared to vehicle-treated mice, PF-04457845-treated mice showed a decrease of cisplatin-induced plasma creatinine, blood urea nitrogen levels, kidney injury biomarkers (NGAL and KIM-1) and renal tubular damage. The renal protection from oral gavage of PF-04457845 against cisplatin-induced nephrotoxicity was associated with an enhanced AEA tone and reduced levels of DNA damage response biomarkers p53 and p21. Our work demonstrates that PF-04457845 effectively alleviates cisplatin-induced nephrotoxicity in mice, underscoring the potential of orally targeting FAAH as a novel strategy to prevent cisplatin nephrotoxicity. Significance Statement Oral administration of FAAH inhibitor, can reduce cisplatin-induced DNA damage response, tubular damages, and kidney dysfunction. Inactivation of FAAH could be a potential strategy to prevent cisplatin-induced nephrotoxicity.

Characterization of a Fatty Acid Amide Hydrolase (FAAH) in Hirudo Verbana

The endocannabinoid system plays a critical role in modulating both peripheral and central nervous system function. Despite being present throughout the animal kingdom, there has been relatively little investigation of the endocannabinoid system beyond traditional animal models. In this study, we report on the identification and characterization of a putative fatty acid amide hydrolase (FAAH) in the medicinal leech, Hirudo verbana. FAAH is the primary enzyme responsible for metabolizing the endocannabinoid signaling molecule arachidonoyl ethanolamide (anandamide or AEA) and therefore plays a critical role in regulating AEA levels in the nervous system. mRNA encoding Hirudo FAAH (HirFAAH) is expressed in the leech central nervous system (CNS) and sequence analysis suggests that this is an orthologue of FAAH-2 observed in vertebrates. Functionally, HirFAAH has serine hydrolase activity based on activity-based protein profiling (ABPP) studies using the fluorophosphonate probe TAMRA-FP. HirFAAH also hydrolyzes arachidonyl 7-amino, 4-methyl coumarin amide (AAMCA), a substrate specific to FAAH. Hydrolase activity during both the ABPP and AAMCA assays was eliminated by a mutation at a conserved catalytic serine. Activity was also blocked by the known FAAH inhibitor, URB597. Treatment of Hirudo ganglia with URB597 potentiated synapses made by the pressure-sensitive mechanosensory neuron (P cell), mimicking the effects of exogenously applied AEA. The Hirudo CNS has been a useful system in which to study properties of endocannabinoid modulation of nociception relevant to vertebrates. Therefore, this characterization of HirFAAH is an important contribution to comparative studies of the endocannabinoid system.

Endogenous Cannabinoids in Crohn’s Disease

Background: An increasing number of people around the world suffer from Crohn’s disease (CD), one of the inflammatory bowel diseases (IBDs). Recent evidence suggests that the endogenous cannabinoid system plays an important role in IBD. The main endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), are ligands of the CB1 and CB2 receptors that are expressed on immune cells. These receptors as well as endocannabinoids are believed to mediate inflammatory activity and participate in the pathophysiology of CD. Objective: Very little is known about the secretion of endogenous cannabinoids throughout the course of CD. Therefore, the aim of this study was to determine and analyze the 2-AG and AEA concentrations in children who suffered from CD. Methods: We studied 34 adolescents with CD, mean age 13.5 years ± 2.0. Blood samples were collected three times in the active phase of the disease (during admission to hospital, before treatment), 2–4 weeks later, during the treatment and clinical improvement of the patients, and 3–6 months later, in the period of remission. The control group included 33 healthy teenagers of the same age who were examined once. In all patients, fasting blood samples were collected in the morning. 2AG and AEA concentrations in serum were measured using EIA kits (Abclonal, Woburn, MA, USA and ELK Biotechnology Co., Ltd. Wuhan, China, respectively). Results: The median 2-AG concentration in the study group was stable: acute phase 907.4 [379.3; 1300.5] pg/mL, during treatment 715.1 [416.7; 1302.5] pg/mL; remission 991.1 [381.1; 1652.5] pg/mL, and similar to the values observed in the control group 761.8 [504.3; 1497.0] pg/mL. No significant differences were found between the results obtained at all time points in the study group and compared to the control group (in all cases p &gt; 0.44). In the case of AEA, in the study group before treatment, the median concentration was 2.63 [2.24; 2.79] ng/mL and similar to values obtained during treatment 2.56 [2.33; 3.06] ng/mL, and in remission, with 2.61 [2.46; 2.85] ng/mL. All these concentrations were lower compared to the values measured in the control group of 3.18 [2.57; 3.88] ng/mL (p = 0.023, p = 0.035, p = 0.056, respectively). Conclusions: While 2-AG levels remained stable throughout the disease course and were comparable to controls, AEA concentrations were consistently lower in CD patients. Therefore, therapeutic interventions aimed at increasing AEA-related signaling, such as administration of its analogues or fatty acid amide hydrolase inhibitors, may improve symptoms associated with Crohn’s disease in children.

Disrupted stress-induced analgesia in a neuropathic pain state is rescued by the endocannabinoid degradation inhibitor JZL195.

Acute stress normally engages descending brain pathways to produce an antinociceptive response, known as stress-induced analgesia. Paradoxically, these descending pain modulatory pathways are also involved in the maintenance of the abnormal pain associated with chronic neuropathic pain. It remains unclear how stress-induced analgesia is affected by neuropathic pain states. We therefore examined the impact of a chronic constriction nerve-injury (CCI) model of neuropathic pain on restraint stress-induced analgesia in C57BL/6 mice. Thirty minutes of restraint stress produced analgesia in the hotplate thermal nociceptive assay that was less in CCI compared to control mice who underwent a sham-surgery. In sham but not CCI mice, stress-induced analgesia was reduced by the opioid receptor antagonist naltrexone. The cannabinoid CB1 receptor antagonist AM281 did not affect stress-induced analgesia in either sham or CCI mice. Low-dose pre-treatment with the dual fatty acid amide hydrolase and monoacylglycerol lipase inhibitor JZL195 increased stress-induced analgesia in CCI but not sham mice. The JZL195 enhancement of stress-induced analgesia in CCI mice was abolished by AM281 but was unaffected by naltrexone. These findings indicate that the acute opioid-mediated analgesic response to a psychological stressor is disrupted in a nerve-injury model of neuropathic pain. Importantly, this impairment of stress-induced analgesia was rescued by blockade of endocannabinoid breakdown via a cannabinoid CB1 receptor dependent mechanism. These findings suggest that subthreshold treatment with endocannabinoid degradation blockers could be used to alleviate the disruption of endogenous pain control systems in a neuropathic pain state.

Endocannabinoid Hydrolase Inhibitors: Potential Novel Anxiolytic Drugs.

Over the past decade, the idea of targeting the endocannabinoid system to treat anxiety disorders has received increasing attention. Previous studies focused more on developing cannabinoid receptor agonists or supplementing exogenous cannabinoids, which are prone to various adverse effects due to their strong pharmacological activity and poor receptor selectivity, limiting their application in clinical research. Endocannabinoid hydrolase inhibitors are considered to be the most promising development strategies for the treatment of anxiety disorders. More recent effortshave emphasized that inhibition of two major endogenous cannabinoid hydrolases, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), indirectly activates cannabinoid receptors by increasing endogenous cannabinoid levels in the synaptic gap, circumventing receptor desensitization resulting from direct enhancement of endogenous cannabinoid signaling. In this review, we comprehensively summarize the anxiolytic effects of MAGL and FAAH inhibitors and their potential pharmacological mechanisms, highlight reported novel inhibitors or natural products, and provide an outlook on future directions in this field.

Potential Therapeutic Targets to Modulate the Endocannabinoid System in Alzheimer's Disease.

Alzheimer's disease (AD), the most common neurodegenerative disease (NDD), is characterized by chronic neuronal cell death through progressive loss of cognitive function. Amyloid beta (Aβ) deposition, neuroinflammation, oxidative stress, and hyperphosphorylated tau proteins are considered the hallmarks of AD pathology. Different therapeutic approaches approved by the Food and Drug Administration can only target a single altered pathway instead of various mechanisms that are involved in AD pathology, resulting in limited symptomatic relief and almost no effect in slowing down the disease progression. Growing evidence on modulating the components of the endocannabinoid system (ECS) proclaimed their neuroprotective effects by reducing neurochemical alterations and preventing cellular dysfunction. Recent studies on AD mouse models have reported that the inhibitors of the fatty acid amide hydrolase (FAAH) and monoacylglycerol (MAGL), hydrolytic enzymes for N-arachidonoyl ethanolamine (AEA) and 2-arachidonoylglycerol (2-AG), respectively, might be promising candidates as therapeutical intervention. The FAAH and MAGL inhibitors alone or in combination seem to produce neuroprotection by reversing cognitive deficits along with Aβ-induced neuroinflammation, oxidative responses, and neuronal death, delaying AD progression. Their exact signaling mechanisms need to be elucidated for understanding the brain intrinsic repair mechanism. The aim of this review was to shed light on physiology and pathophysiology of AD and to summarize the experimental data on neuroprotective roles of FAAH and MAGL inhibitors. In this review, we have also included CB1R and CB2R modulators with their diverse roles to modulate ECS mediated responses such as anti-nociceptive, anxiolytic, and anti-inflammatory actions in AD. Future research would provide the directions in understanding the molecular mechanisms and development of new therapeutic interventions for the treatment of AD.

Cannabidiol and positive effects on object recognition memory in an in vivo model of Fragile X Syndrome: Obligatory role of hippocampal GPR55 receptors

Cannabidiol (CBD), a non-psychotomimetic constituent of Cannabis sativa, has been recently approved for epileptic syndromes often associated with Autism spectrum disorder (ASD). However, the putative efficacy and mechanism of action of CBD in patients suffering from ASD and related comorbidities remain debated, especially because of the complex pharmacology of CBD. We used pharmacological, immunohistochemical and biochemical approaches to investigate the effects and mechanisms of action of CBD in the recently validated Fmr1-Δexon 8 rat model of ASD, that is also a model of Fragile X Syndrome (FXS), the leading monogenic cause of autism. CBD rescued the cognitive deficits displayed by juvenile Fmr1-Δexon 8 animals, without inducing tolerance after repeated administration. Blockade of CA1 hippocampal GPR55 receptors prevented the beneficial effect of both CBD and the fatty acid amide hydrolase (FAAH) inhibitor URB597 in the short-term recognition memory deficits displayed by Fmr1-Δexon 8 rats. Thus, CBD may exert its beneficial effects through CA1 hippocampal GPR55 receptors. Docking analysis further confirmed that the mechanism of action of CBD might involve competition for brain fatty acid binding proteins (FABPs) that deliver anandamide and related bioactive lipids to their catabolic enzyme FAAH. These findings demonstrate that CBD reduced cognitive deficits in a rat model of FXS and provide initial mechanistic insights into its therapeutic potential in neurodevelopmental disorders.

Indirect and direct cannabinoid agonists differentially affect mesolimbic dopamine release and related behaviors.

The cannabinoid system is being researched as a potential pharmaceutical target for a multitude of disorders. The present study examined the effect of indirect and direct cannabinoid agonists on mesolimbic dopamine release and related behaviors in C57BL/6J (B6) mice. The indirect cannabinoid agonist N-arachidonoyl serotonin (AA-5-HT) indirectly agonizes the cannabinoid system by preventing the metabolism of endocannabinoids through fatty acid amide hydrolase inhibition while also inhibiting transient receptor potential vanilloid Type 1 channels. Effects of AA-5-HT were compared with the direct cannabinoid receptor Type 1 agonist arachidonoyl-2'-chloroethylamide (ACEA). In Experiment 1, mice were pretreated with seven daily injections of AA-5-HT, ACEA, or vehicle prior to assessments of locomotor activity using open field (OF) testing and phasic dopamine release using in vivo fixed potential amperometry. Chronic exposure to AA-5-HT did not alter locomotor activity or mesolimbic dopamine functioning. Chronic exposure to ACEA decreased rearing and decreased phasic dopamine release while increasing the dopaminergic response to cocaine. In Experiment 2, mice underwent AA-5-HT, ACEA, or vehicle conditioned place preference, then saccharin preference testing, a measure commonly associated with anhedonia. Mice did not develop a conditioned place preference or aversion for AA-5-HT or ACEA, and repeated exposure to AA-5-HT or ACEA did not alter saccharin preference. Altogether, the findings suggest that neither of these drugs induce behaviors that are classically associated with abuse liability in mice; however, direct cannabinoid receptor Type 1 agonism may play more of a role in mediating mesolimbic dopamine functioning than indirect cannabinoid agonism. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Evaluating Fatty Acid Amide Hydrolase as a Suitable Target for Sleep Promotion in a Transgenic TauP301S Mouse Model of Neurodegeneration.

Sleep disruption is an expected component of aging and neurodegenerative conditions, including Alzheimer's disease (AD). Sleep disruption has been demonstrated as a driver of AD pathology and cognitive decline. Therefore, treatments designed to maintain sleep may be effective in slowing or halting AD progression. However, commonly used sleep aid medications are associated with an increased risk of AD, highlighting the need for sleep aids with novel mechanisms of action. The endocannabinoid system holds promise as a potentially effective and novel sleep-enhancing target. By using pharmacology and genetic knockout strategies, we evaluated fatty acid amide hydrolase (FAAH) as a therapeutic target to improve sleep and halt disease progression in a transgenic Tau P301S (PS19) model of Tauopathy and AD. We have recently shown that PS19 mice exhibit sleep disruption in the form of dark phase hyperarousal as an early symptom that precedes robust Tau pathology and cognitive decline. Acute FAAH inhibition with PF3845 resulted in immediate improvements in sleep behaviors in male and female PS19 mice, supporting FAAH as a potentially suitable sleep-promoting target. Moreover, sustained drug dosing for 5-10 days resulted in maintained improvements in sleep. To evaluate the effect of chronic FAAH inhibition as a possible therapeutic strategy, we generated FAAH-/- PS19 mice models. Counter to our expectations, FAAH knockout did not protect PS19 mice from progressive sleep loss, neuroinflammation, or cognitive decline. Our results provide support for FAAH as a novel target for sleep-promoting therapies but further indicate that the complete loss of FAAH activity may be detrimental.

A fluorogenic substrate for the detection of lipid amidases in intact cells

Lipid amidases of therapeutic relevance include acid ceramidase (AC), N-acylethanolamine-hydrolyzing acid amidase, and fatty acid amide hydrolase (FAAH). Although fluorogenic substrates have been developed for the three enzymes and high-throughput methods for screening have been reported, a platform for the specific detection of these enzyme activities in intact cells is lacking. In this article, we report on the coumarinic 1-deoxydihydroceramide RBM1-151, a 1-deoxy derivative and vinilog of RBM14-C12, as a novel substrate of amidases. This compound is hydrolyzed by AC (appKm = 7.0 μM; appVmax = 99.3 nM/min), N-acylethanolamine-hydrolyzing acid amidase (appKm = 0.73 μM; appVmax = 0.24 nM/min), and FAAH (appKm = 3.6 μM; appVmax = 7.6 nM/min) but not by other ceramidases. We provide proof of concept that the use of RBM1-151 in combination with reported irreversible inhibitors of AC and FAAH allows the determination in parallel of the three amidase activities in single experiments in intact cells.

Social stress-induced depressive-like symptoms and changes in gut microbial and lipidomic profiles are prevented by pharmacological inhibition of FAAH activity in male rats

Pharmacological inhibition of fatty acid amide hydrolase (FAAH) activity has antidepressant-like effects in preclinical models of stress. In this study, we investigated whether the antidepressant-like effects of FAAH inhibition are associated with corresponding changes in gut microbial and lipidomic profiles, which are emerging as critical components in the pathophysiology of depression. Adult male Wistar rats experienced five weeks of repeated social defeat or control procedure and were treated with the FAAH inhibitor URB694 (0.3 mg/kg/day, i.p.) or vehicle starting from the third week. Repeated social defeat induced the emergence of depressive-like behavioral (sucrose preference reduction and passive coping behaviors in the forced swim test) and neuroendocrine (increased corticosterone levels) changes, which were prevented by URB694 treatment. Repeated social defeat also provoked a significant variation in gut microbiota (changes in the relative abundance of 14 bacterial taxa) and lipidic (e.g., glycerophospholipids) composition. These stress-induced changes were prevented by URB694 treatment. These findings indicate that inhibition of FAAH activity with URB694 blocks the co-occurrence of depressive-like behavioral and neuroendocrine changes and alterations in gut microbial and lipid composition in rats exposed to repeated social defeat. In conclusion, these results suggest that the gut microbiota-lipid crosstalk may represent a novel biological target for FAAH inhibitors to enhance stress resilience.

Novel dual-target FAAH and TRPV1 ligands as potential pharmacotherapeutics for pain management

Dual-acting drugs that simultaneously inhibit fatty acid amide hydrolase (FAAH) and antagonize the transient receptor potential vanilloid 1 (TRPV1) is a promising stronger therapeutic approach for pain management without side effects associated with single-target agents. Here, several series of dual FAAH/TRPV1 blockers were designed and synthesized through rational molecular hybridization between the pharmacophore of classical TRPV1 antagonists and FAAH inhibitors. The studies resulted in compound 2r, which exhibited strong dual FAAH/TRPV1 inhibition/antagonism in vitro, exerted powerful analgesic effects in formalin-induced pain test (phase II, in mice), desirable anti-inflammatory activity in carrageenan-induced paw edema in rats, no TRPV1-related hyperthermia side effect, and favorable pharmacokinetic properties. Meanwhile, the contributions of TRPV1 and FAAH to its antinociceptive effects were verified by target engagement and molecular docking studies. Overall, compound 2r can serve as a new scaffold for developing FAAH/TRPV1 dual-activie ligands to counteract pain.

Alleviating CB2-Dependent ER Stress and Mitochondrial Dysfunction Improves Chronic Cerebral Hypoperfusion-Induced Cognitive Impairment

Augmentation of endoplasmic reticulum (ER) stress may trigger excessive oxidative stress, which induces mitochondrial dysfunction. The fatty acid amide hydrolase inhibitor, URB597, shows anti-oxidation characteristics in multiple neurological disorders. The present study aimed to determine whether inhibition of ER stress was involved in the protective effects of URB597 against chronic cerebral hypoperfusion (CCH)-induced cognitive impairment. Hippocampal HT-22 cells were exposed to oxygen-glucose deprivation. The cell viability, apoptosis, ER stress, mitochondrial ATP, and oxidative stress levels were assessed following treatment with URB597, benzenebutyric acid (4-PBA), and thapsigargin (TG). Furthermore, the effects of URB597 on ER stress and related pathways were investigated in the CCH animal model, including Morris water maze testing of cognition, western blotting analysis of ER stress signaling, and transmission electron microscopy of mitochondrial and ER ultrastructure changes. The results suggested that cerebral ischemia caused ER stress with upregulation of ER stress signaling-related proteins, mitochondrial dysfunction, neuronal apoptosis, ultrastructural injuries of mitochondria-associated ER membranes, and cognitive decline. Co-immunoprecipitation experiments confirmed the interaction between CB2 and β-Arrestin1. Inhibiting ER stress by URB597 improved these changes by activating CB2/β-Arrestin1 signaling, which was reversed by the CB2 antagonist, AM630. Together, the results identified a novel mechanism of URB597, involving CCH-induced cognitive impairment alleviation of CB2-dependent ER stress and mitochondrial dysfunction. Furthermore, this study identified CB2 as a potential target for therapy of ischemic cerebrovascular diseases.Graphical

Synthesis of Stilbenyl and Bibenzyl Cannabinoids and Analysis of Their Cannabimimetic Potential

AbstractEfficient syntheses of stilbenyl and bibenzyl cannabinoids were investigated. A comprehensive synthetic strategy without protecting groups was constructed on direct C–C condensation and [3+3] annulation followed by different intramolecular cyclizations or reductive aromatization. In total, 14 cannabinoids representing chemical diversity were tested for their effect on cannabinoid receptors CB1 and CB2, and their inhibitory activity on fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) in vitro. Interestingly, different bibenzyl cannabinoids showed moderately potent nanomolar activity. One exception was a stilbenyl cannabichromene, which was characterized as a substance that may have psychoactive properties. Only a bibenzyl cannabidiol showed a significant inhibition of FAAH. The structure–activity relationships of the synthesized cannabinoids are discussed. Our data show the versatility of the cannabinoid scaffold to generate nature-inspired cannabimimetics.

Function of Presynaptic Inhibitory Cannabinoid CB1 Receptors in Spontaneously Hypertensive Rats and Its Modification by Enhanced Endocannabinoid Tone.

We studied whether the function of presynaptic inhibitory cannabinoid CB1 receptors on the sympathetic nerve fibres innervating resistance vessels is increased in spontaneously hypertensive rats (SHR) like in deoxycorticosterone (DOCA)-salt hypertension. An increase in diastolic blood pressure (DBP) was induced by electrical stimulation of the preganglionic sympathetic neurons or by phenylephrine injection in pithed SHR and normotensive Wistar-Kyoto rats (WKY). The electrically (but not the phenylephrine) induced increase in DBP was inhibited by the cannabinoid receptor agonist CP55940, similarly in both groups, and by the endocannabinoid reuptake inhibitor AM404 in SHR only. The effect of CP55940 was abolished/reduced by the CB1 receptor antagonist AM251 (in both groups) and in WKY by endocannabinoid degradation blockade, i.e., the monoacylglycerol lipase (MAGL) inhibitor MJN110 and the dual fatty acid amide hydrolase (FAAH)/MAGL inhibitor JZL195 but not the FAAH inhibitor URB597. MJN110 and JZL195 tended to enhance the effect of CP55940 in SHR. In conclusion, the function of presynaptic inhibitory CB1 receptors depends on the hypertension model. Although no differences occurred between SHR and WKY under basal experimental conditions, the CB1 receptor function was better preserved in SHR when the endocannabinoid tone was increased by the inhibition of MAGL or the endocannabinoid transporter.

Effect of MCH1, a fatty-acid amide hydrolase inhibitor, on the depressive-like behavior and gene expression of endocannabinoid and dopaminergic-signaling system in the mouse nucleus accumbens.

MCH1 is a synthetic macamide that has shown in vitro inhibitory activity on fatty acid amide hydrolase (FAAH), an enzyme responsible for endocannabinoid metabolism. This inhibition can modulate endocannabinoid and dopamine signaling in the nucleus accumbens (NAc), potentially having an antidepressant-like effect. The present study aimed to evaluate the effect of the in vivo administration of MCH1 (3, 10, and 30 mg/kg, ip) in 2-month-old BALB/c male mice (n=97) on forced swimming test (FST), light-dark box (LDB), and open field test (OFT) and on early gene expression changes 2 h after drug injection related to the endocannabinoid system (Cnr1 and Faah) and dopaminergic signaling (Drd1 and Drd2) in the NAc core. We found that the 10 mg/kg MCH1 dose reduced the immobility time compared to the vehicle group in the FST with no effect on anxiety-like behaviors measured in the LDB or OFT. However, a 10 mg/kg MCH1 dose increased locomotor activity in the OFT compared to the vehicle. Moreover, RT-qPCR results showed that the 30 mg/kg MCH1 dose increased Faah gene expression by 2.8-fold, and 10 mg/kg MCH1 increased the Cnr1 gene expression by 4.3-fold compared to the vehicle. No changes were observed in the expression of the Drd1 and Drd2 genes in the NAc at either MCH1 dose. These results indicated that MCH1 might have an antidepressant-like effect without an anxiogenic effect and induces significant changes in endocannabinoid-related genes but not in genes of the dopaminergic signaling system in the NAc of mice.