Goods and Bads of the Endocannabinoid System as a Therapeutic Target: Lessons Learned after 30 Years

Enhanced visualization of endocannabinoids spatial distribution in mouse brain via MALDI-2 mass spectrometry imaging

Endocannabinoids (eCBs) are endogenous lipid messengers that primarily bind cannabinoid receptors CB1/CB2 and together with the enzymes that regulate their biosynthesis and degradation define the endocannabinoid system. The eCB signaling system plays a key role in the central nervous system, and results often altered in neurological disorders. The analysis of eCBs is challenging due to their low concentration in biospecimens, and this is exacerbated in Mass Spectrometry Imaging (MSI) where low sensitivity and tissue dependent ion suppression obscure their spatial visualization. In this work we address this limitation by the application of laser-induced post-ionization (MALDI-2) approach. Herein we demonstrate that MALDI-2 boosts the detection of 2-arachidonylglycerol (2-AG) and N-acylethanolamines (AEA, PEA, OEA) with respect to MALDI, and that eCBs can be visualized in brain at physiological concentration only by MALDI-2-MSI. Root-mean-square (RMS), Total ion count (TIC) and internal standards (I.S.) normalization were evaluated, with I.S. normalization providing improved pixel to pixel variation and more uniform distribution for 2-AG and PEA in specific brain regions. Furthermore, high spatial resolution up to 5 μm pixel size was evaluated, resulting in the detection of all eCBs and confirming the MALDI-2 potential even reducing the ablated tissue amount. As proof of concept, the method was applied to map eCBs in a mouse model of mild traumatic brain injury, the APP-SWE mice, highlighting differences in the modulation of eCBs in Cortex, Hippocampus and Hypothalamus, suggesting the ability to reveal valuable biological insights for neuropharmacology.

Efficacy of cannabidiol alone or in combination with Δ-9-tetrahydrocannabinol for the management of substance use disorders: An umbrella review of the evidence

BACKGROUND AND AIMS

Substance use disorders (SUD) lead to a high burden of disease, yet treatment options are limited. Cannabidiol (CBD) is being investigated as a potential therapeutic target due to its pharmacological properties and mode of action in the endocannabinoid system. Recent systematic reviews (SR) on CBD and SUDs have shown inconsistent results. The objective of this umbrella review was to determine whether CBD alone or in combination with Δ-9-tetrahydrocannabinol (THC) is effective for managing and treating SUDs.

METHODS

Following a registered protocol, we searched PubMed, Web of Science and Epistemonikos databases for SRs, with or without a meta-analysis, of randomized controlled trials focusing on interventions dispensing CBD, alone or in combination with THC, to treat SUDs, published from 1 January 2000 to 15 October 2024. Screening, data extraction and quality assessment with the AMSTAR 2 tool were performed by two researchers in parallel and duplicated.

RESULTS

22 SRs were included, 5 of which performed a meta-analysis. We found mixed evidence regarding the efficacy of CBD to manage and treat SUDs. Findings were interpreted in light of the quality of the SRs. Nabiximols, which contains CBD and THC, demonstrated positive effects on cannabis withdrawal and craving symptoms. Evidence supporting the efficacy of CBD is limited and inconclusive for abstinence, reduction or cessation of use of cannabis, tobacco, alcohol, opiates and other psychoactive substances.

CONCLUSION

Cannabidiol (CBD) monotherapy does not appear to be efficacious for treatment of substance use disorders. CBD primarily exhibits effects on cannabis withdrawal and craving when combined with Δ-9-tetrahydrocannabinol (THC). Existing data on the efficacy of CBD alone with regard to other outcomes related to substance use disorders are limited.

Integrating endocannabinoid signaling, CCK interneurons, and hippocampal circuit dynamics in behaving animals

The brain's endocannabinoid signaling system modulates a diverse range of physiological phenomena and is also involved in various psychiatric and neurological disorders. The basic components of the molecular machinery underlying endocannabinoid-mediated synaptic signaling have been known for decades. However, limitations associated with the short-lived nature of endocannabinoid lipid signals had made it challenging to determine the spatiotemporal specificity and dynamics of endocannabinoid signaling in vivo. Here, we discuss how novel technologies have recently enabled unprecedented insights into endocannabinoid signaling taking place at specific synapses in behaving animals. In this review, we primarily focus on cannabinoid-sensitive inhibition in the hippocampus in relation to place cell properties to illustrate the potential of these novel methodologies. In addition, we highlight implications of these approaches and insights for the unraveling of cannabinoid regulation of synapses in vivo in other brain circuits in both health and disease.

Probing Native CB2 Receptor Mobility in Plasma Membranes of Living Cells by Fluorescence Recovery After Photobleaching

In this study, we employed a novel fluorescent probe, RO7304924 - which selectively targets cannabinoid 2 receptor (CB2R) - to assess the lateral mobility of CB2R within the plasma membrane of Chinese hamster ovary cells stably expressing a functional, untagged receptor variant. Utilizing confocal fluorescence recovery after photobleaching (FRAP), we quantified the diffusion coefficient and mobile fraction of CB2R, thereby demonstrating the efficacy of RO7304924 as an innovative tool for elucidating the dynamics of this major endocannabinoid-binding G protein-coupled receptor. Our present findings highlight the potential of combining advanced ligand-based fluorescent probes with FRAP for future investigations into the biochemical details of CB2R mobility in living cells, and its impact on receptor-dependent cellular processes.

A universal cannabinoid CB1 and CB2 receptor TR-FRET kinetic ligand-binding assay

Introduction

The kinetics of ligand binding to G protein-coupled receptors (GPCRs) is an important optimization parameter in drug discovery. Traditional radioligand assays are labor-intensive, preventing their application at the early stages of drug discovery. Fluorescence-based assays offer several advantages, including a possibility to develop a homogeneous format, continuous data collection, and higher throughput. This study sought to develop a fluorescence-based binding assay to investigate ligand-binding kinetics at human cannabinoid type 1 and 2 receptors (CB1R and CB2R).

Methods

We synthesized D77, a novel tracer derived from the non-selective cannabinoid Δ8-THC. Using time-resolved Förster resonance energy transfer (TR-FRET), we developed an assay to study ligand-binding kinetics at physiological temperatures. For CB1R, we truncated the first 90 amino acids of its flexible N-terminal domain to reduce the FRET distance between the terbium cryptate (donor) and the fluorescent ligand (acceptor). The full-length CB2R construct was functional without modification due to its shorter N-terminus. The Motulsky-Mahan competition binding model was used to analyze the binding kinetics of the endocannabinoids and several other non-fluorescent ligands.

Results

The D77 tracer showed nanomolar-range affinity for truncated CB1R (CB1R91-472) and full-length CB2R (CB2R1-360), displaying competitive binding with orthosteric ligands. D77 exhibited rapid dissociation kinetics from both CB1R and CB2R, which were similar to the fastest dissociating reference compounds. This was critical for accurately determining the on- and off-rates of the fastest dissociating compounds. Using D77, we measured the kinetic binding properties of various CB1R and CB2R agonists and antagonists at physiological temperature and sodium ion concentration.

Discussion

The k on values for molecules binding to CB1R varied by three orders of magnitude, from the slowest (HU308) to the fastest (rimonabant). A strong correlation between k on and affinity was observed for compounds binding to CB1R, indicating that the association rate primarily determines their affinity for CB1R. Unlike CB1R, a stronger correlation was found between the dissociation rate constant k off and the affinity for CB2R, suggesting that both k on and k off dictate the overall affinity for CB2R. Exploring the kinetic parameters of cannabinoid drug candidates could help drug development programs targeting these receptors.

FAAH Modulators from Natural Sources: A Collection of New Potential Drugs

The endocannabinoid system (ECS) plays a crucial role in maintaining homeostasis by regulating immune response, energy metabolism, cognitive functions, and neuronal activity. It consists of endocannabinoids (eCBs), cannabinoid receptors (CBRs), and enzymes involved in eCB biosynthesis and degradation. Increasing evidence highlights the involvement of the ECS under several pathological conditions, making it a promising therapeutic target. Recent research efforts have focused on modulating endogenous eCB levels, particularly through the inhibition of fatty acid amide hydrolase (FAAH), the main catabolic enzyme of the major eCB anandamide. Natural substances, including plant extracts and purified compounds, can inhibit FAAH and represent a promising area of pharmacological research. Natural FAAH inhibitors are particularly attractive due to their potentially lower toxicity compared to synthetic compounds, making them safer candidates for therapeutic applications. Phytocannabinoids, flavonoids, and flavolignans have been shown to efficiently inhibit FAAH. The structural diversity and bioactivity of these natural substances provide a valuable alternative to synthetic inhibitors, and may open new avenues for developing innovative pharmacological tools.

Recent Progress in N-Acylethanolamine Research: Biological Functions and Metabolism Regulated by Two Distinct N-Acyltransferases: cPLA2ε and PLAAT Enzymes

N-Acylethanolamines (NAEs) are a class of lipid mediators that consist of long-chain fatty acids condensed with ethanolamine and exert various biological activities depending on their fatty acyl groups. NAEs are biosynthesized from membrane phospholipids by two-step reactions or alternative multi-step reactions. In the first reaction, N-acyltransferases transfer an acyl chain from the sn-1 position of phospholipids to the amino group (N position) of phosphatidylethanolamine (PE), generating N-acyl-PE (NAPE), a precursor of NAE. So far, two types of N-acyltransferases have been identified with different levels of Ca2+-dependency: cytosolic phospholipase A2 ε (cPLA2ε) as a Ca2+-dependent N-acyltransferase and phospholipase A and acyltransferase (PLAAT) enzymes as Ca2+-independent N-acyltransferases. Recent in vivo studies using knockout mice with cPLA2ε and PLAAT enzymes, combined with lipidomic approaches, have clarified their roles in the skin and brain and in other physiological events. In this review, we summarize the current understanding of the functions and properties of these enzymes.

Comprehensive mini-review: therapeutic potential of cannabigerol - focus on the cardiovascular system

Backgrounds

Cannabigerol (CBG) is a non-psychoactive phytocannabinoid with a broad spectrum of biological effects. However, there is still too little research on its safety especially its effects on the cardiovascular system. Due to its agonist effects on alpha-2-adrenergic receptors (α2AR), it is speculated that it may have applications in the pharmacotherapy of metabolic syndrome, particularly hypertension. Thus, the aim of our review was to analyse the therapeutic potential of CBG in cardiovascular diseases.

Methods

The review was based on searches of the PubMed and Web of Science databases. Keywords were used to identify literature containing therapeutic and mechanistic information on CBG and its potential effects on the cardiovascular system.

Results

A review of the literature shows that CBG exhibits hypotensive effects in mice probably through α2AR agonism. Other numerous in vitro and in vivo studies show that CBG has anti-inflammatory, antioxidant effects and also regulates cell apoptosis. Cannabigerol improved tissue sensitivity to insulin, and also showed efficacy in inhibiting platelet aggregation. However, there are reports of adverse effects of high doses of CBG on liver architecture and function, which calls into question its usefulness and safety profile.

Conclusion

Above mentioned beneficial properties of CBG suggest that it may be useful in treating hypertension and metabolic syndrome. However, there is still a lack of studies on the chronic administration of CBG and its effects on cardiovascular parameters in hypertension condition, which may be necessary to determine its safety and the need for future studies on other indications.

NAPE-PLD is target of thiazide diuretics

Thiazide and thiazide-like diuretics are among the most efficacious and used drugs for the treatment of hypertension, edema, and major cardiovascular outcomes. Despite more then than six decades of clinical use, the molecular target and mechanism of action by which these drugs cure hypertension after long-term use have remained mysterious. Here we report the discovery and validation of a previously unknown renal and extrarenal target of these antihypertensives, the membrane-associated phospholipase N-acylphosphatidylethanolamine-specific phospholipase D (NAPE-PLD) of the endocannabinoid system. Structural and functional insights, together with preclinical studies in hypertensive rats, disclose the molecular and physiological basis by which thiazides cause acute diuresis and, at the same time, the distinctive chronic reduction of vascular resistance. Our results shed light on the mechanism of treatment of hypertension and will be useful for developing more efficacious medications for the management of vascular risk factors, as well as associated leukoencephalopathies and myelin disorders.

Development of a Highly Selective NanoBRET Probe to Assess MAGL Inhibition in Live Cells

Cell-free enzymatic assays are highly useful tools in early compound profiling due to their robustness and scalability. However, their inadequacy to reflect the complexity of target engagement in a cellular environment may lead to a significantly divergent pharmacology that is eventually observed in cells. The discrepancy that emerges from properties like permeability and unspecific protein binding may largely mislead lead compound selection to undergo further chemical optimization. We report the development of a new intracellular NanoBRET assay to assess MAGL inhibition in live cells. Based on a reverse design approach, a highly potent, reversible preclinical inhibitor was conjugated to the cell-permeable BODIPY590 acceptor fluorophore while retaining its overall balanced properties. An engineered MAGL-nanoluciferase (Nluc) fusion protein provided a suitable donor counterpart for the facile interrogation of intracellular ligand activity. Validation of assay conditions using a selection of known MAGL inhibitors set the stage for the evaluation of over 1'900 MAGL drug candidates derived from our discovery program. This evaluation enabled us to select compounds for further development based not only on target engagement, but also on favorable physicochemical parameters like permeability and protein binding. This study highlights the advantages of cell-based target engagement assays for accelerating compound profiling and progress at the early stages of drug discovery programs.

The PLAAT family as phospholipid-related enzymes

The phospholipase A and acyltransferase (PLAAT) family is a group of structurally related proteins that are conserved among vertebrates. In humans, the family comprises five members (PLAAT1-5), which share common domain structures, and functions as phospholipase A1/A2 and acyltransferase enzymes. Regarding acyltransferase activities, PLAATs produce N-acyl-phosphatidylethanolamines, which serve as the precursor of bioactive N-acylethanolamines (NAEs). Recent evidence strongly suggests that PLAAT proteins play a crucial role in maintaining homeostasis in various organelles, such as the endoplasmic reticulum, lysosomes, mitochondria, and peroxisomes. In this process, PLAAT proteins bind to organelles and degrade them in an enzyme activity-dependent manner. Their physiological significance was revealed by the inability of PLAAT-deficient animals to degrade organelles during the maturation of the eye lens, resulting in the development of cataracts. Furthermore, the deficiency of PLAAT1, 3, and 5 in mice caused resistance to high-fat diet-induced fatty liver, the lean phenotype represented by a marked decrease in adipose tissue mass, and the exacerbation of testicular inflammation due to decreased levels of anti-inflammatory NAEs, respectively. In addition, human PLAAT3 was identified as a causative gene for lipodystrophy. We herein provide an overview of the molecular and biological properties of PLAAT proteins.

Age- and sex-dependent participation of the endocannabinoid system in locomotion and risk assessment of an ADHD rat model

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder affecting individuals across age groups. Impairments in executive function characterize ADHD and are often associated with elevated levels of risk-taking behaviors. The endocannabinoid system plays a crucial role in modulating prefrontal cortex circuits. Here, we assessed the effects of acute pharmacological manipulation of cannabinoid CB1 and CB2 receptors on locomotion and risk assessment/anxiety-like behaviors in an ADHD animal model during adolescence and adulthood. Further, we investigated the protein levels and gene expression of endocannabinoid system components (CB1, CB2, FAAH, MAGL) in the prefrontal cortex at both ages. During adolescence, activation of cannabinoid receptors aggravated the hyperactivity and risky behaviors of the ADHD model. These behavioral traits were more evident in female rats. In adulthood, manipulation of cannabinoid receptors did not alter hyperactivity but worsened risk assessment. Overall, gene expression levels of receptors and enzymes of the endocannabinoid system were increased in the ADHD model. Our findings suggest that the endocannabinoid system may operate differently in ADHD, and manipulating this system, especially in adolescents, could exacerbate deficits in inhibitory control.

CANBERRA: A Phase II Randomized Clinical Trial to Test the Therapeutic Potential of Oral Vicasinabin in Diabetic Retinopathy

Objective

Nonproliferative diabetic retinopathy (NPDR) is a progressive disease that can lead to blindness. Current therapies for NPDR are invasive and not extensively used or accessible until the disease progresses, pointing to the need for an early noninvasive treatment. The objective of CANBERRA was to assess the safety, tolerability, and efficacy of oral administration of vicasinabin (RG7774) on the severity of diabetic retinopathy (DR) in participants with moderately severe to severe NPDR and good vision.

Design

CANBERRA was a global, multicentric randomized, double-masked, parallel-group, placebo-controlled, phase II study. The study duration was 36 months.

Participants

A total of 139 treatment-naïve patients with type 1 or type 2 diabetes mellitus and Diabetic Retinopathy Severity Scale (DRSS) levels of 47 or 53 in ≥1 eye were enrolled.

Intervention

Eligible patients were randomized 1:1:1 to 36 weeks of daily oral placebo, vicasinabin 30 mg, or vicasinabin 200 mg. Participants were followed for an additional 12 weeks.

Main Outcome Measures

The primary safety objective was to evaluate the safety and tolerability of vicasinabin by the frequency and severity of adverse events (AEs). The primary efficacy objective was to assess the effect of vicasinabin on the severity of DR, assessing the proportion of participants with ≥2-step improvement in DRSS from baseline at week 36 in the study eye.

Results

Results are presented in the following order: placebo, vicasinabin 30 mg, vicasinabin 200 mg; 47, 48, and 44 participants were enrolled. Baseline characteristics were balanced. Adherence to treatment was approximately 90%, and pharmacokinetic analysis showed dose-dependent plasma exposure to vicasinabin. The primary efficacy endpoint was not met: the percentage of participants who improved their DRSS by ≥2 steps at week 36 from baseline were 7.9, 9.5, and 5.7, without statistically significant differences. The systemic and ocular safety profiles of vicasinabin were favorable, and AEs distributed evenly across arms. Vicasinabin did not induce changes in glycemic control or any kidney function or cardiovascular parameters. Three patients in the placebo arm discontinued the study due to serious AEs not related to the drug.

Conclusions

At the doses tested, vicasinabin did not improve DRSS in participants with NPDR. The role of the cannabinoid system in DR remains elusive.

Trial Registration

ClinicalTrials.gov identifier: NCT04265261. EUDRACT number: 2019-002067-10.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Role of Nanomedicine in Transforming Pharmacotherapy for Substance Use Disorder (SUD)

The field of nanomedicine offers revolutionary potential to reshape the discovery and development of therapeutics for diverse human diseases. However, its application has been limited in improving Substance Use Disorders (SUDs), which represent a profound public health crisis, including major types such as opioid, alcohol, stimulant, and cannabis use disorders. Pharmacotherapy, a cornerstone of SUD management, has reduced morbidity, mortality, and the societal impact of addiction, though its efficacy has ranged from none to moderate. Thus, there is a major unmet need to transform SUD pharmacotherapy to curb the epidemic of addiction. This article explores the potential roles of nanomedicine-inspired precision-targeted drug delivery, sustained release, and combination therapies to increase therapeutic efficacy and minimize side effects. Additionally, it discusses innovative mechanisms that align with the neurobiological complexities of addiction and synergistic approaches that integrate nanomedicine with behavioral interventions, device-based therapies, and emerging modalities such as immunotherapy and neurostimulation. Despite these advancements, barriers such as treatment accessibility, adherence challenges, and inequitable resource distribution persist, particularly in underserved populations. By harnessing the transformative capabilities of nanomedicine and integrating it into holistic, equitable, and personalized care frameworks, this review highlights a path forward to revolutionize the SUD pharmacotherapy landscape. The article underscores the need for continued nano-SUD pharmacotherapy research and the development of strategies to alleviate the substantial burden of addiction on individuals, families, and society.

The endocannabinoid 2-arachidonoylglycerol is released and transported on demand via extracellular microvesicles

While it is known that endocannabinoids (eCB) modulate multiple neuronal functions, the molecular mechanism governing their release and transport remains elusive. Here, we propose an "on-demand release" model, wherein the formation of microvesicles, a specific group of extracellular vesicles (EVs) containing the eCB, 2-arachidonoylglycerol (2-AG), is an important step. A coculture model system that combines a reporter cell line expressing the fluorescent eCB sensor, G protein-coupled receptor-based (GRAB)eCB2.0, and neuronal cells revealed that neurons release EVs containing 2-AG, but not anandamide, in a stimulus-dependent process regulated by protein kinase C, Diacylglycerol lipase, Adenosinediphosphate (ADP) ribosylation factor 6 (Arf6), and which was sensitive to inhibitors of eCB facilitated diffusion. A vesicle contained approximately 2,000 2-AG molecules. Accordingly, hippocampal eCB-mediated synaptic plasticity was modulated by Arf6 and transport inhibitors. The "on-demand release" model, supported by mathematical analysis, offers a cohesive framework for understanding eCB trafficking at the molecular level and suggests that microvesicles carrying signaling lipids in their membrane regulate neuronal functions in parallel to canonical synaptic vesicles.

Aframomum melegueta Seed Extract's Effects on Anxiety, Stress, Mood, and Sleep: A Randomized, Double-Blind, Pilot Clinical Trial

Background and aims:Aframomum melegueta (A. melegueta) from the ginger family is appreciated for its pungent seeds widely used in African ethno-medicine. Among the several biological activities associated with the seed's preparations, some preclinical studies suggest a set of neuroactive properties that have not been tested in humans to date. We performed a clinical trial to investigate the effects of A. melegueta seed extracts on anxiety, stress, mood, and sleep in healthy subjects with moderate anxiety levels. In vitro pharmacological assays targeting the endocannabinoid, serotoninergic, and GABAergic systems were conducted to elucidate the underlying mechanism of action. Methods:A. melegueta standardized to 10% total vanilloids (primarily 6-gingerol, 6-shogaol, and 6-paradol) was obtained after hydroalcoholic extraction and the spray-drying microencapsulation process. Subjects consumed 50, 100, or 150 mg of the extract daily for two days. A set of validated psychometric test questionnaires was collected before and 48 h after the first intake. A. melegueta extract interaction with canonical endocannabinoid receptors (hCB1R and hCB2R), the serotonin receptor (5HT1AR) and gamma-aminobutyric acid receptor (GABAA1R) was evaluated by the radioligand binding assay. Additionally, receptor functional assays and enzyme inhibition assays were conducted to test the extract's functional activity on the non-canonical endocannabinoid receptor (TRPV1) and the cannabinoid fatty-acid amide hydrolase enzyme (FAAH), respectively. Results: In vitro pharmacological tests showed that the A. melegueta extract activated TRPV1, modulated both hCB2R and 5HT1AR and inhibited FAAH, which is the enzyme primarily responsible for hydrolyzing endogenous anandamide. After a 48 h intake period, the extract significantly reduced anxiety and tension related to stress, improved overall mood, and enhanced sleep quality in the participants at doses ranging from 50 to 150 mg, with no reported side effects. Conclusions: This study supports the potential of the A. melegueta extract for anxiety reduction, mood improvement, stress mitigation, and sleep enhancement. The in vitro tests suggest that the extract's primary mechanism of action may involve the inhibition of FAAH, which is a key target in anxiety management.

Carboxylesterase 1-mediated endocannabinoid metabolism in skin: role in melanoma progression in BRafV600E/Pten-/- mice

BACKGROUND

Melanoma is a highly aggressive skin cancer with a poor prognosis. The endocannabinoids 2-arachidonoylgylcerol (2-AG) and anandamide have been linked to melanoma progression, though their roles remain unclear. We hypothesized that the 2-AG-arachidonate-prostaglandin axis could drive aggressive melanoma progression.

METHODS

The genetically engineered melanoma mouse model B6-Tyr::CreERT2; BRafCA; PtenloxP was characterized by targeted metabolomics. Functionally expressed serine hydrolases in the tumor tissue were identified by chemoproteomics. Pharmacological inhibition of carboxylesterase 1 (CES1) was achieved through chronic in vivo i.p. treatment with JZL184 (10 mg/kg daily), confirmed by activity-based protein profiling (ABPP) and targeted lipidomics. CES1-mediated 2-AG hydrolysis was further confirmed in radiotracer-based assays using CES1-transfected cell lines.

RESULTS

The diacylglycerol and protein kinase C activator 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG) was significantly elevated in the nodular-like melanoma tissues, along with 2-AG and arachidonic acid (ARA), compared to normal skin. AEA and other N-acylethanolamines were decreased, while, notably, prostaglandin levels remained unchanged. Significant changes in the levels of neuromodulators and neurotransmitters, including serotonin and adenosine, were observed. Pronounced differences between serine hydrolase activity in normal skin and melanoma tissue were identified by ABPP. Intriguingly, CES1 was identified as the only 2-AG-hydrolyzing enzyme in this melanoma tissue, as MAGL and ABHD6/12 were not expressed. The MAGL inhibitor JZL184 also efficiently inhibited CES1 in vitro and in vivo, increasing glycerol esters and reducing tumor progression. Additionally, scRNA-seq data from previous studies revealed divergent MAGL/CES1 expression patterns across different human melanoma subtypes.

CONCLUSIONS

A role of CES1 expression in skin is demonstrated for the first time. Our study suggests that 2-AG degradation to arachidonate favors melanoma progression, either reflecting the carcinogenic role of ARA or that monoacylglycerols like 2-AG and/or other CES1 substrates may exert antitumor effects, indicating that CES1 could be a potential therapeutic target. CES1 expression and high SAG, 2-AG, and ARA levels may be a signature of specific BRAF-driven malignant melanoma subtypes which are associated with discrete metabolic adaptations.

Therapeutic potential of cannabidiol polypharmacology in neuropsychiatric disorders

Cannabidiol (CBD), the primary non-intoxicating compound in cannabis, is currently approved for treating rare, treatment-resistant seizures. Recent preclinical research suggests that CBD's multifaceted mechanisms of action in the brain, which involve multiple molecular targets, underlie its neuroprotective, anti-inflammatory, anxiolytic, and antipsychotic effects. Clinical trials are also exploring CBD's therapeutic potential beyond its current uses. This review focuses on CBD's polypharmacological profile and discusses the latest preclinical and clinical findings regarding its efficacy in neuropsychiatric disorders. Existing evidence suggests that CBD's ability to modulate multiple signaling pathways may benefit neuropsychiatric disorders, and we propose further research areas to clarify its mechanisms, address data gaps, and refine its therapeutic indications.

Alterations of endocannabinoid signaling and microglia reactivity in the retinas of AD-like mice precede the onset of hippocampal β-amyloid plaques

Extra-cerebral manifestations of Alzheimer's disease (AD) develop in the retina, which is, therefore, considered a "window to the brain". Recent studies demonstrated the dysregulation of the endocannabinoid (eCB) system (ECS) in AD brain. Here, we explored the possible alterations of ECS and the onset of gliosis in the retina of AD-like mice. Tg2576 (TG) mice overexpressing the amyloid precursor protein (APP) were used at the age of 12 months, when hippocampal β-amyloid plaques had not been developed yet. Analysis of retinal gliosis showed a significant increase in the number of IBA1 (+) microglia cells in TG versus wild type (WT). Gliosis was not associated with retinal β-amyloid plaques, evident retinal degenerative signatures, or excitotoxicity; instead, oxidative stress burden was observed as increased acrolein levels. Analysis of the ECS (receptors/metabolic enzymes) through western blotting (WB) revealed the up-regulation of cannabinoid receptor 2 (CB2) and monoacylglycerol lipase (MAGL), the enzyme responsible for the degradation of 2-arachidonoylglycerol (2-AG), in TG retinas. Fluorescence intensity analysis of anti-CB2 and anti-MAGL immuno-stained cryosections was consistent with WB, showing their up-regulation throughout the retinal layers. No statistically significant differences were found for the other enzymes/receptors of the ECS under study. However, linear regression analysis for individual animals showed a significant correlation between CB2 and fatty acid amide hydrolase (FAAH), diacylglycerol lipase α/β (DAGLα/β), and APP; instead, a significant negative correlation was found between MAGL and APP. Finally, ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) demonstrated a significant reduction of 2-AG in TG retinas (~0.34 ng/mg) compared to WT (~1.70 ng/mg), while a trend toward increase was found for the other eCB anandamide (AEA). Overall, our data indicate that gliosis and ECS dysregulation-in particular of CB2, MAGL and 2-AG-occur in the retina of AD-like mice before retinal degeneration and development of hippocampal β-amyloid plaques.

∆9-Tetrahydrocannabinol Increases Growth Factor Release by Cultured Adipose Stem Cells and Adipose Tissue in vivo

BACKGROUND

Because of its biocompatibility and its soft and dynamic nature, the grafting of adipose tissue is regarded an ideal technique for soft-tissue repair. The adipose stem cells (ASCs) contribute significantly to the regenerative potential of adipose tissue, because they can differentiate into adipocytes and release growth factors for tissue repair and neovascularization to facilitate tissue survival. The present study tested the effect of administering a chronic low dose of ∆9-tetrahydrocannabinol (THC) on these regenerative properties, in vitro and in vivo.

METHODS

Human ASCs were exposed to increasing concentrations of THC. Resazurin conversion was applied to investigate the effect on metabolic activity, cell number was assessed by crystal violet staining, tri-linear differentiation was evaluated by specific colorimetric approaches, and the release of growth factors was analyzed by ELISA. Two groups of mice were treated daily either with a low dose of THC (3 mg/kg) or a vehicle solution. After 3 weeks, adipose tissue was obtained from excised fat deposits, homogenized and tested for growth factor contents.

RESULTS

THC decreased ASC proliferation but increased metabolic activity as well as adipogenic and chondrogenic differentiation. A low concentration of THC (1 µM) enhanced the growth factor release by ASCs. The concentration of these cytokines was also increased in adipose tissue of mice treated with THC.

CONLUSION

Our results indicate that chronic activation of the endocannabinoid system promoted differentiation and growth factor release of ASCs, which could be of specific value for enhancing the regenerative potential of adipose tissue.

CBD for pets: navigating quality assurance, safety standards, and marketing strategies

As the human cannabinoid (CBD) market grows, there is an inevitable transfer of the same or similar products into the veterinary sector. Advances in veterinary medicine and care of companion animals has led to extended life expectancy and consequently, there is an increased incidence of age-related chronic conditions that compromise quality of life. CBD products may alleviate these conditions. Research into CBD for companion animal species is on the rise, however, we found that there are no licensed veterinary CBD products available in the market due to a lack of appropriate testing and/or data. Here we outline the data that is available and show that the regulatory, and safety considerations around these products needs further consideration and this encompasses many products currently available on the market. Changes in regulations and further research for quality assurance are paramount to distribution of safe and applicable products for companion animals.

Fatty-acid amide hydrolase inhibition mitigates Alzheimer's disease progression in mouse models of amyloidosis

The endocannabinoid N-arachidonoylethanolamine (AEA) is a pro-homeostatic bioactive lipid known for its anti-inflammatory, anti-oxidative, immunomodulatory, and neuroprotective properties, which may contrast/mitigate Alzheimer's disease (AD) pathology. This study explores the therapeutic potential of targeting fatty acid amide hydrolase (FAAH), the major enzyme degrading AEA, in mouse models of amyloidosis (APP/PS1 and Tg2576). Enhancing AEA signaling by genetic deletion of FAAH delayed cognitive deficits in APP/PS1 mice and improved cognitive symptoms in 12-month-old AD-like mice. Chronic pharmacological FAAH inhibition fully reverted neurocognitive decline, attenuated neuroinflammation, and promoted neuroprotective mechanisms in Tg2576 mice. Additionally, pharmacological FAAH inhibition robustly suppressed β-amyloid production and accumulation, associated with decreased expression of β-site amyloid precursor protein cleaving enzyme 1 (BACE1), possibly through a cannabinoid receptor 1-dependent epigenetic mechanism. These findings improve our understanding of AEA signaling in AD pathogenesis and provide proof of concept that selective targeting of FAAH activity could be a promising therapeutic strategy against AD.

Structural basis of THC analog activity at the Cannabinoid 1 receptor

Tetrahydrocannabinol (THC) is the principal psychoactive compound derived from the cannabis plant Cannabis sativa and approved for emetic conditions, appetite stimulation and sleep apnea relief. THC's psychoactive actions are mediated primarily by the cannabinoid receptor CB1. Here, we determine the cryo-EM structure of HU210, a THC analog and widely used tool compound, bound to CB1 and its primary transducer, Gi1. We leverage this structure for docking and 1000 ns molecular dynamics simulations of THC and 10 structural analogs delineating their spatiotemporal interactions at the molecular level. Furthermore, we pharmacologically profile their recruitment of Gi and β-arrestins and reversibility of binding from an active complex. By combining detailed CB1 structural information with molecular models and signaling data we uncover the differential spatiotemporal interactions these ligands make to receptors governing potency, efficacy, bias and kinetics. This may help explain the actions of abused substances, advance fundamental receptor activation studies and design better medicines.

Chemical Probes for Investigating the Endocannabinoid System

Cannabis sativa has been used therapeutically since early civilizations, with key cannabinoids Δ9-tetrahydrocannabinol (THC) 3.1 and cannabidiol characterized in the 1960s, leading to the discovery of cannabinoid receptors type 1 (CB1R) and type 2 (CB2R) and the endocannabinoid system (ECS) in the 1990s. The ECS, involving endogenous ligands like 2-arachidonoylglycerol (2-AG) 1.1, anandamide (N-arachidonoylethanolamine (AEA)) 1.2, and various proteins, regulates vital processes such as sleep, appetite, and memory, and holds significant therapeutic potential, especially for neurological disorders. Small molecule-derived pharmacological tools, or chemical probes, target key components of the ECS and are crucial for target validation, mechanistic studies, pathway elucidation, phenotypic screening, and drug discovery. These probes selectively interact with specific proteins or pathways, enabling researchers to modulate target activity and observe biological effects. When they carry an additional reporter group, they are referred to as labeled chemical probes. Developed through medicinal chemistry, structural biology, and high-throughput screening, effective chemical probes must be selective, potent, and depending on their purpose meet additional criteria such as cell permeability and metabolic stability.This chapter describes high-quality labeled and unlabeled chemical probes targeting ECS constituents that have been successfully applied for various research purposes. CB1R and CB2R, class A G protein-coupled receptors, are activated by 2-AG 1.1, AEA 1.2, and THC 3.1, with numerous ligands developed for these receptors. Imaging techniques like single-photon emission computed tomography, positron emission tomography, and fluorescently labeled CB1R and CB2R probes have enhanced CB receptor studies. CB2R activation generally results in immunosuppressive effects, limiting tissue injury. AEA 1.2 is mainly degraded by fatty acid amide hydrolase (FAAH) or N-acylethanolamine acid amidase (NAAA) into ethanolamine and arachidonic acid (AA) 1.3. FAAH inhibitors increase endogenous fatty acid amides, providing analgesic effects without adverse effects. NAAA inhibitors reduce inflammation and pain in animal models. Diacylglycerol lipase (DAGL) is essential for 2-AG 1.1 biosynthesis, while monoacylglycerol lipase (MAGL) degrades 2-AG 1.1 into AA 1.3, thus regulating cannabinoid signaling. Multiple inhibitors targeting FAAH and MAGL have been generated, though NAAA and DAGL probe development lags behind. Similarly, advancements in inhibitors targeting endocannabinoid (eCB) cellular uptake or trafficking proteins like fatty acid-binding proteins have been slower. The endocannabinoidome (eCBome) includes the ECS and related molecules and receptors, offering therapeutic opportunities from non-THC cannabinoids and eCBome mediators. Ongoing research aims to refine chemical tools for ECS and eCBome study, addressing unmet medical needs in central nervous system disorders and beyond.

Cannabinol modulates the endocannabinoid system and shows TRPV1-mediated anti-inflammatory properties in human keratinocytes

Cannabinol (CBN) is a secondary metabolite of cannabis whose beneficial activity on inflammatory diseases of human skin has attracted increasing attention. Here, we sought to investigate the possible modulation by CBN of the major elements of the endocannabinoid system (ECS), in both normal and lipopolysaccharide-inflamed human keratinocytes (HaCaT cells). CBN was found to increase the expression of cannabinoid receptor 1 (CB1) at gene level and that of vanilloid receptor 1 (TRPV1) at protein level, as well as their functional activity. In addition, CBN modulated the metabolism of anandamide (AEA) and 2-arachidonoylglicerol (2-AG), by increasing the activities of N-acyl phosphatidylethanolamines-specific phospholipase D (NAPE-PLD) and fatty acid amide hydrolase (FAAH)-the biosynthetic and degradative enzyme of AEA-and that of monoacylglycerol lipase (MAGL), the hydrolytic enzyme of 2-AG. CBN also affected keratinocyte inflammation by reducing the release of pro-inflammatory interleukin (IL)-8, IL-12, and IL-31 and increasing the release of anti-inflammatory IL-10. Of note, the release of IL-31 was mediated by TRPV1. Finally, the mitogen-activated protein kinases (MAPK) signaling pathway was investigated in inflamed keratinocytes, demonstrating a specific modulation of glycogen synthase kinase 3β (GSK3β) upon treatment with CBN, in the presence or not of distinct ECS-directed drugs. Overall, these results demonstrate that CBN modulates distinct ECS elements and exerts anti-inflammatory effects-remarkably via TRPV1-in human keratinocytes, thus holding potential for both therapeutic and cosmetic purposes.

The Anticancer Activity of Cannabinol (CBN) and Cannabigerol (CBG) on Acute Myeloid Leukemia Cells

Several cannabis plant-derived compounds, especially cannabinoids, exhibit therapeutic potential in numerous diseases and conditions. In particular, THC and CBD impart palliative, antiemetic, as well as anticancer effects. The antitumor effects include inhibition of cancerous cell growth and metastasis and induction of cell death, all mediated by cannabinoid interaction with the endocannabinoid system (ECS). However, the exact molecular mechanisms are still poorly understood. In addition, their effects on leukemia have scarcely been investigated. The current work aimed to assess the antileukemic effects of CBN and CBG on an acute monocytic leukemia cell line, the THP-1. THP-1 cell viability, morphology and cell cycle analyses were performed to determine potential cytotoxic, antiproliferative, and apoptotic effects of CBN and CBG. Western blotting was carried out to measure the expression of the proapoptotic p53. Both CBN and CBG inhibited cell growth and induced THP-1 cell apoptosis and cell cycle arrest in a dose- and time-dependent manner. CBN and CBG illustrated different dosage effects on THP-1 cells in the MTT assay (CBN > 40 μΜ, CBG > 1 μM) and flow cytometry (CBN > 5 μM, CBG > 40 μM), highlighting the cannabinoids' antileukemic activity. Our study hints at a direct correlation between p53 expression and CBG or CBN doses exceeding 50 μM, suggesting potential activation of p53-associated signaling pathways underlying these effects. Taken together, CBG and CBN exhibited suppressive, cell death-inducing effects on leukemia cells. However, further in-depth research will be needed to explore the molecular mechanisms driving the anticancer effects of CBN and CBG in the leukemia setting.

Research and Clinical Practice Involving the Use of Cannabis Products, with Emphasis on Cannabidiol: A Narrative Review

BACKGROUND

Emerging evidence supports cannabidiol (CBD) as a promising therapeutic compound for various health conditions, despite its approval as a medication (product for medical purposes) remaining restricted to a limited range of clinical indications. Simultaneously, the regulation of cannabis-derived products for medicinal and recreational use has expanded their global market availability to meet local community demands. This scenario presents a complex challenge for clinicians, researchers, and industry, as the global appeal of therapeutic uses of CBD is growing more rapidly than the scientific evidence supporting its safety and effectiveness.

OUTCOMES

A narrative review was conducted to discuss the best evidence regarding the pharmacological profile of CBD, its efficacy, and safety within the context of regulation and perspectives on the development of new cannabinoid-based drugs. Key articles addressing the various facets of this issue were selected for comprehensive analysis.

CONCLUSIONS

Clinicians and researchers may face unique challenges in understanding the pharmacological profile of CBD and the prospects for developing its clinical indications, given the heterogeneity of clinical terminologies and the quality and composition of cannabis-based medical products available on the market. More basic and clinical research that complies with regulatory agencies' testing guidelines, such as good manufacturing practices (GMPs), good laboratory practices (GLPs), and good clinical practices (GCPs), is needed to obtain approval for CBD or any other cannabinoid as a therapeutic for broader clinical indications.

Cannabinoid Hyperemesis Syndrome (CHS) - An emerging gastrointestinal disorder and clinical challenge

Nausea and vomiting are not uncommon symptoms resulting in emergency department (ED) or primary care visits. One of the emerging etiologies - Cannabinoid Hyperemesis Syndrome (CHS) remains significantly under-diagnosed, often resulting in unnecessary repeat ED visits and testing. This is in part due to lack of experience with and knowledge about CHS by health care professionals. Characterized by cyclic vomiting, often severe and intractable, it is frequently associated with a form of self-treatment; the compulsive need to take hot showers, and in the context of chronic cannabis use. With increased legalization and resultant accessibility to cannabis containing products, the risk of adverse events is significantly rising. Lack of clinical familiarity with the range of potential deleterious physical and mental health effects associated with cannabis leads to delays in appropriate diagnosis and effective treatment of CHS. Moreover, commonly utilized anti-emetics, such as ondansetron, and similar 5 HT drugs may not fully attenuate symptoms of CHS, and other interventions may be necessary; ultimately abstinence being the most effective long term clinical preventive approach. The objective of this review article is to assist the clinician in identifying the specific clinical characteristics of CHS, distinguishing it from other causes of CVS or nausea and vomiting, to facilitate more rapid, effective interventions. Collaboration with substance use professionals should also be considered during CHS treatment.

Cannabinoid receptor 2 (CB2) modulators: A patent review (2016-2024)

Cannabinoid receptors CB1 and CB2 play critical roles in regulating numerous central and peripheral physiological activities. While efforts have been made to develop ligands for both CB1 and CB2 receptors, CB1 receptor ligands often have restricted use due to undesirable psychotropic side effects. Consequently, recent cannabis research has increasingly focused on CB2-specific ligands. Pharmacological agonists of CB2 receptors have shown potential in managing pain, inflammation, arthritis, neuroprotection, cancer, and other disorders. Despite several CB2 receptor ligands entering clinical trials, none have achieved market approval except natural cannabinoids and their derivatives, primarily due to insufficient CB2/CB1 receptor selectivity. However, new-generation ligands developed in recent years have demonstrated improved selectivity. This review covers patent literature on CB2 modulators from 2016 to 2024, highlighting the major advances in the field. During this period, the majority of research has concentrated on using CB2 modulators to alleviate inflammation and pain. Additionally, patents have explored CB2 modulators for a range of specific diseases, including: psychiatric and neuropsychiatric disorders, schizophrenia, multiple myeloma and osteoporosis, ocular inflammation and neuropathic Pain, cancer anorexia and weight loss, antioxidant and anti-aging agents, lymphocytopenia, hearing loss, Alzheimer's disease, cancer and non-malignant tumors. Notably, recent years have seen increased interest in CB2 antagonists/inverse agonists, with few candidates advancing to clinical studies. Significant progress has been made in the synthesis and modulation of selective CB2 agonists and antagonists, paving the way for future developments in CB2 modulators. This review provides insights and prospects for the continued evolution of CB2-targeted therapies.

Charting the therapeutic landscape: a comprehensive evidence map on medical cannabis for health outcomes

The therapeutic potential of medical cannabis has garnered significant attention in recent years, prompting an urgent need for a comprehensive understanding of its effectiveness across various health outcomes. This article presents an Evidence Map that systematically summarizes clinical evidence on the use of medical cannabis, including the health conditions it addresses, the interventions employed, and the resulting clinical outcomes. The objective is to map the effectiveness of medical cannabis in relation to a wide range of health outcomes. The systematic review process involved two independent, blinded literature researchers who screened the search output using Rayyan software. For studies deemed relevant, full texts were obtained to clarify inclusion or exclusion criteria, and any disagreements were resolved through group discussion. Out of 1,840 initial references, 279 potential studies were selected and read in full, resulting in the inclusion of 194 studies in this evidence map. The results highlight the use of various cannabis formulations, including those based on isolated cannabidiol (CBD). Seventy-one distinct health outcomes were identified in the systematic reviews, with the most reported outcomes being related to various types of pain and patient safety. Other frequently studied outcomes included appetite regulation, chemotherapy-induced nausea and vomiting, and muscle spasticity. Notably, 278 out of 489 descriptions of treatment effects for these health outcomes reported either "Positive" or "Potentially Positive" effects. When considering only high-quality systematic reviews, as evaluated by the AMSTAR 2 tool, 42 out of 67 descriptions of treatment effects for up to 20 health outcomes were classified as "Positive" or "Potentially Positive." These outcomes included pain, insomnia, seizures, anxiety, muscle spasticity, multiple sclerosis, urinary incontinence, anorexia, and patient safety. This evidence map provides a comprehensive overview of the current clinical evidence on medical cannabis, highlighting its potential therapeutic benefits across a range of health conditions and emphasizing the need for further high-quality research.

The Entourage Effect in Cannabis Medicinal Products: A Comprehensive Review

This study explores the complementary or synergistic effects of medicinal cannabis constituents, particularly terpenes, concerning their therapeutic potential, known as the entourage effect. A systematic review of the literature on cannabis "entourage effects" was conducted using the PRISMA model. Two research questions directed the review: (1) What are the physiological effects of terpenes and terpenoids found in cannabis? (2) What are the proven "entourage effects" of terpenes in cannabis? The initial approach involved an exploratory search in electronic databases using predefined keywords and Boolean phrases across PubMed/MEDLINE, Web of Science, and EBSCO databases using Medical Subject Headings (MeSH). Analysis of published studies shows no evidence of neuroprotective or anti-aggregatory effects of α-pinene and β-pinene against β-amyloid-mediated toxicity; however, modest lipid peroxidation inhibition by α-pinene, β pinene, and terpinolene may contribute to the multifaceted neuroprotection properties of these C. sativa L. prevalent monoterpenes and the triterpene friedelin. Myrcene demonstrated anti-inflammatory proprieties topically; however, in combination with CBD, it did not show significant additional differences. Exploratory evidence suggests various therapeutic benefits of terpenes, such as myrcene for relaxation; linalool as a sleep aid and to relieve exhaustion and mental stress; D-limonene as an analgesic; caryophyllene for cold tolerance and analgesia; valencene for cartilage protection; borneol for antinociceptive and anticonvulsant potential; and eucalyptol for muscle pain. While exploratory research suggests terpenes as influencers in the therapeutic benefits of cannabinoids, the potential for synergistic or additive enhancement of cannabinoid efficacy by terpenes remains unproven. Further clinical trials are needed to confirm any terpenes "entourage effects."

Cannabis, Endocannabinoids and Brain Development: From Embryogenesis to Adolescence

The endocannabinoid signalling system (ECS) plays a critical role from the very beginning of embryogenesis. Accordingly, the ECS is engaged early on in nervous system development, starting from neurulation, supported by the identification of ECS components-both receptors and enzymes controlling endocannabinoid metabolism-at these early stages. In particular, regarding the brain, the ECS is involved in the tightly regulated sequence of events that comprise brain development, from neurogenesis to neuronal migration, morphological guidance for neuronal connectivity, and synaptic circuitry refinement. The importance of this broad role of the ECS across various brain development processes is further underscored by the growing understanding of the consequences of cannabis exposure at different developmental stages. Despite the considerable knowledge we have on the role of the ECS in brain development, significant gaps in our understanding remain, particularly regarding the long-term impact and underlying mechanisms of cannabis exposure at different developmental stages. This review provides an overview of the current state of knowledge on the role of the ECS throughout brain development, from embryogenesis to adulthood, and discusses the impact of cannabis exposure, especially during adolescence-a critical period of circuitry maturation and refinement coinciding with an increased risk of cannabis use.

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.

Endocannabinoid System and Metabolism: The Influences of Sex

The endocannabinoid system (ECS) is a lipid signaling system involved in numerous physiological processes, such as endocrine homeostasis, appetite control, energy balance, and metabolism. The ECS comprises endocannabinoids, their cognate receptors, and the enzymatic machinery that tightly regulates their levels within tissues. This system has been identified in various organs, including the brain and liver, in multiple mammalian and non-mammalian species. However, information regarding the sex-specific regulation of the ECS remains limited, even though increasing evidence suggests that interactions between sex steroid hormones and the ECS may ultimately modulate hepatic metabolism and energy homeostasis. Within this framework, we will review the sexual dimorphism of the ECS in various animal models, providing evidence of the crosstalk between endocannabinoids and sex hormones via different metabolic pathways. Additionally, we will underscore the importance of understanding how endocrine-disrupting chemicals and exogenous cannabinoids influence ECS-dependent metabolic pathways in a sex-specific manner.

Structure-Guided Discovery of cis-Hexahydro-pyrido-oxazinones as Reversible, Drug-like Monoacylglycerol Lipase Inhibitors

Monoacylglycerol lipase (MAGL) is a key enzyme involved in the metabolism of the endogenous signaling ligand 2-arachidonoylglycerol, a neuroprotective endocannabinoid intimately linked to central nervous system (CNS) disorders associated with neuroinflammation. In the quest for novel MAGL inhibitors, a focused screening approach on a Roche library subset provided a reversible benzoxazinone hit exhibiting high ligand efficiency. The subsequent design of the three-dimensional cis-hexahydro-pyrido-oxazinone (cis-HHPO) moiety as benzoxazinone replacement enabled the combination of high MAGL potency with favorable ADME properties. Through enzymatic resolution an efficient synthetic route of the privileged cis-(4R,8S) HHPO headgroup was established, providing access to the highly potent and selective MAGL inhibitor 7o. Candidate molecule 7o matches the target compound profile of CNS drugs as it achieves high CSF exposures after systemic administration in rodents. It engages with the target in the brain and modulates neuroinflammatory processes, thus holding great promise for the treatment of CNS disorders.

Cannabis and Cannabinoid Signaling: Research Gaps and Opportunities

Cannabis and its products have been used for centuries for both medicinal and recreational purposes. The recent widespread legalization of cannabis has vastly expanded its use in the United States across all demographics except for adolescents. Meanwhile, decades of research have advanced our knowledge of cannabis pharmacology and particularly of the endocannabinoid system with which the components of cannabis interact. This research has revealed multiple targets and approaches for manipulating the system for therapeutic use and to ameliorate cannabis toxicity or cannabis use disorder. Research has also led to new questions that underscore the potential risks of its widespread use, particularly the enduring consequences of exposure during critical windows of brain development or for consumption of large daily doses of cannabis with high content Δ 9-tetrahydrocannabinol. This article highlights current neuroscience research on cannabis that has shed light on therapeutic opportunities and potential adverse consequences of misuse and points to gaps in knowledge that can guide future research. SIGNIFICANCE STATEMENT: Cannabis use has escalated with its increased availability. Here, the authors highlight the challenges of cannabis research and the gaps in our knowledge of cannabis pharmacology and of the endocannabinoid system that it targets. Future research that addresses these gaps is needed so that the endocannabinoid system can be leveraged for safe and effective use.

Δ9-Tetrahydrocannabinol Alleviates Hyperalgesia in a Humanized Mouse Model of Sickle Cell Disease

People with sickle cell disease (SCD) often experience chronic pain as well as unpredictable episodes of acute pain, which significantly affects their quality of life and life expectancy. Current treatment strategies for SCD-associated pain primarily rely on opioid analgesics, which have limited efficacy and cause serious adverse effects. Cannabis has emerged as a potential alternative, yet its efficacy remains uncertain. In this study, we investigated the antinociceptive effects of Δ9-tetrahydrocannabinol (THC), cannabis' intoxicating constituent, in male HbSS mice, which express >99% human sickle hemoglobin, and male HbAA mice, which express normal human hemoglobin A, as a control. Acute THC administration (0.1-3 mg/kg-1, i.p.) dose-dependently reduced mechanical and cold hypersensitivity in human sickle hemoglobin (HbSS) but not human normal hemoglobin A (HbAA) mice. In the tail-flick assay, THC (1 and 3 mg/kg-1, i.p.) produced substantial antinociceptive effects in HbSS mice. By contrast, THC (1 mg/kg-1, i.p.) did not alter anxiety-like behavior (elevated plus maze) or long-term memory (24-hour novel object recognition). Subchronic THC treatment (1 and 3 mg/kg-1, i.p.) provided sustained relief of mechanical hypersensitivity but led to tolerance in cold hypersensitivity in HbSS mice. Together, the findings identify THC as a possible therapeutic option for the management of chronic pain in SCD. Further research is warranted to elucidate its mechanism of action and possible interaction with other cannabis constituents. SIGNIFICANCE STATEMENT: The study explores Δ9-tetrahydrocannabinol (THC)'s efficacy in alleviating pain in sickle cell disease (SCD) using a humanized mouse model. Findings indicate that acute THC administration reduces mechanical and cold hypersensitivity in SCD mice without impacting emotional and cognitive dysfunction. Subchronic THC treatment offers sustained relief of mechanical hypersensitivity but leads to cold hypersensitivity tolerance. These results offer insights into THC's potential as an alternative pain management option in SCD, highlighting both its benefits and limitations.

Comparative targeted lipidomics between serum and cerebrospinal fluid of multiple sclerosis patients shows sex and age-specific differences of endocannabinoids and glucocorticoids

Multiple sclerosis (MS) is a complex chronic neuroinflammatory disease characterized by demyelination leading to neuronal dysfunction and neurodegeneration manifested by various neurological impairments. The endocannabinoid system (ECS) is a lipid signalling network, which plays multiple roles in the central nervous system and the periphery, including synaptic signal transmission and modulation of inflammation. The ECS has been identified as a potential target for the development of novel therapeutic interventions in MS patients. It remains unclear whether ECS-associated metabolites are changed in MS and could serve as biomarkers in blood or cerebrospinal fluid (CSF). In this retrospective study we applied targeted lipidomics to matching CSF and serum samples of 74 MS and 80 non-neuroinflammatory control patients. We found that MS-associated lipidomic changes overall did not coincide between CSF and serum. While glucocorticoids correlated positively, only the endocannabinoid (eCB) 2-arachidonoyl glycerol (2-AG) showed a weak positive correlation (r = 0.3, p < 0.05) between CSF and serum. Peptide endocannabinoids could be quantified for the first time in CSF but did not differ between MS and controls. MS patients showed elevated levels of prostaglandin E2 and steaorylethanolamide in serum, and 2-oleoylglycerol and cortisol in CSF. Sex-specific differences were found in CSF of MS patients showing increased levels of 2-AG and glucocorticoids in males only. Overall, arachidonic acid was elevated in CSF of males. Interestingly, CSF eCBs correlated positively with age only in the control patients due to the increased levels of eCBs in young relapsing-remitting MS patients. Our findings reveal significant discrepancies between CSF and serum, underscoring that measuring eCBs in blood matrices is not optimal for detecting MS-associated changes in the central nervous system. The identified sex and age-specific changes of analytes of the stress axis and ECS specifically in the CSF of MS patients supports the role of the ECS in MS and may be relevant for drug development strategies.

Visualization of membrane localization and the functional state of CB2R pools using matched agonist and inverse agonist probe pairs

The diversity of physiological roles of the endocannabinoid system has turned it into an attractive yet elusive therapeutic target. However, chemical probes with various functionalities could pave the way for a better understanding of the endocannabinoid system at the cellular level. Notably, inverse agonists of CB2R - a key receptor of the endocannabinoid system - lagged behind despite the evidence regarding the therapeutic potential of its antagonism. Herein, we report a matched fluorescent probe pair based on a common chemotype to address and visualize both the active and inactive states of CB2R, selectively. Alongside extensive cross-validation by flow cytometry, time-lapse confocal microscopy, and super-resolution microscopy, we successfully visualize the intracellular localization of CB2R pools in live cells. The synthetic simplicity, together with the high CB2R-selectivity and specificity of our probes, turns them into valuable tools in chemical biology and drug development that can benefit the clinical translatability of CB2R-based drugs.

Homodimerization of CB2 cannabinoid receptor triggered by a bivalent ligand enhances cellular signaling

G protein-coupled receptors (GPCRs) exist within a landscape of interconvertible conformational states and in dynamic equilibrium between monomers and higher-order oligomers, both influenced by ligand binding. Here, we show that a homobivalent ligand formed by equal chromenopyrazole moieties as pharmacophores, connected by 14 methylene units, can modulate the dynamics of the cannabinoid CB2 receptor (CB2R) homodimerization by simultaneously binding both protomers of the CB2R-CB2R homodimer. Computational and pharmacological experiments showed that one of the ligand pharmacophores binds to the orthosteric site of one protomer, and the other pharmacophore to a membrane-oriented pocket between transmembranes 1 and 7 of the partner protomer. This results in unique pharmacological properties, including increased potency in Gi-mediated signaling and enhanced recruitment of β-arrestin. Thus, by modulating dimerization dynamics, it may be possible to fine-tune CB2R activity, potentially leading to improved therapeutic outcomes.

Protective effects of fatty acid amide hydrolase inhibition in UVB-activated microglia

Neuroinflammation is a hallmark of several neurodegenerative disorders that has been extensively studied in recent years. Microglia, the primary immune cells of the central nervous system (CNS), are key players in this physiological process, demonstrating a remarkable adaptability in responding to various stimuli in the eye and the brain. Within the complex network of neuroinflammatory signals, the fatty acid N-ethanolamines, in particular N-arachidonylethanolamine (anandamide, AEA), emerged as crucial regulators of microglial activity under both physiological and pathological states. In this study, we interrogated for the first time the impact of the signaling of these bioactive lipids on microglial cell responses to a sub-lethal acute UVB radiation, a physical stressor responsible of microglia reactivity in either the retina or the brain. To this end, we developed an in vitro model using mouse microglial BV-2 cells. Upon 24 h of UVB exposure, BV-2 cells showed elevated oxidative stress markers and, cyclooxygenase (COX-2) expression, enhanced phagocytic and chemotactic activities, along with an altered immune profiling. Notably, UVB exposure led to a selective increase in expression and activity of fatty acid amide hydrolase (FAAH), the main enzyme responsible for degradation of fatty acid ethanolamides. Pharmacological FAAH inhibition via URB597 counteracted the effects of UVB exposure, decreasing tumor necrosis factor α (TNF-α) and nitric oxide (NO) release and reverting reactive oxidative species (ROS), interleukin-1β (IL-1β), and interleukin-10 (IL-10) levels to the control levels. Our findings support the potential of enhanced fatty acid amide signaling in mitigating UVB-induced cellular damage, paving the way to further exploration of these lipids in light-induced immune responses.

CNS Drug Discovery in Academia: Where Basic Research Meets Innovation

The involvement of academic research in drug discovery is consistently growing. However, academic projects seldom advance to clinical trials. Here, we assess the landscape of drug discovery within the National Centre of Competence in Research (NCCR) TransCure launched by the Swiss National Science Foundation to foster basic research and early-stage drug discovery on membrane transporters. This included transporters in central nervous system (CNS) disorders, which represent a huge unmet medical need. While idea championship, sustainable funding, collaborations between disciplines at the interface of academia and industry are important for translational research, Popperian falsifiability, strong intellectual property and a motivated startup team are key elements for innovation. This is exemplified by the NCCR TransCure spin-off company Synendos Therapeutics, a clinical stage biotech company developing the first selective endocannabinoid reuptake inhibitors (SERIs) as novel treatment for neuropsychiatric disorders. We provide a perspective on the challenges related to entering an uncharted druggable space and bridging the often mentioned "valley of death". The high attrition rate of drug discovery projects in the CNS field within academia is often due to the lack of meaningful animal models that can provide pharmacological proof-of-concept for potentially disruptive technologies at the earliest stages, and the absence of solid intellectual property.

Endocannabinoid system and phytocannabinoids in the main species of veterinary interest: a comparative review

Since the discovery of the endocannabinoid system and due to the empirical evidence of the therapeutic effects on several illnesses both in humans and animals that follow the administration of exogenous cannabinoids (i.e., phytocannabinoids), numerous studies have been conducted. These investigations aimed to identify the expression and distribution of cannabinoid receptors in healthy and pathologic organs and tissues of different animal species and to define the interactions of phytocannabinoids with these receptors. In the last decade, pharmacokinetics, efficacy and tolerability of many Cannabis derivatives formulations, mainly containing cannabidiol, in the main species of veterinary interest, have been also investigated. This manuscript summarizes the findings reported by the scientific studies published so far on the molecular mode of action of the main phytocannabinoids, the localization of cannabinoid receptors in organs and tissues, as well as the pharmacokinetics, efficacy and tolerability of Cannabis derivatives in dogs, cats, horses and other species of veterinary interest. A deep knowledge of these issues is crucial for the use of phytocannabinoids for therapeutic purposes in animal species.

Associations of Cannabis Use, Metabolic Dysfunction-Associated Steatotic Liver Disease, and Liver Fibrosis in U.S. Adults

Introduction: Following the introduction of metabolic dysfunction-associated steatotic liver disease (MASLD) as a replacement term for nonalcoholic fatty liver disease, the relationship between MASLD and cannabis use has yet to be established. With the global rise in cannabis consumption, understanding its impact on MASLD is critical for clinical guidance. Our study investigated the association between cannabis use, MASLD, and clinically significant fibrosis (CSF) among U.S. adults. Methods: Data were collected from the National Health and Nutrition Examination Survey for the period 2017 to 2018 to conduct a cross-sectional analysis. The diagnosis of hepatic steatosis and CSF was based on median values of the controlled attenuation parameter and liver stiffness measurement, with thresholds of 285 dB/m and 8.6 kPa, respectively. Information on cannabis use was obtained through self-report questionnaires. Multinomial logistic regression models and subgroup analyses were used to investigate the association between cannabis use and MASLD with CSF. Results: Our study assessed data from 2,756 U.S. adults (51.1% female; 32.2% white; mean age 39.41 ± 11.83 years), who had complete information on liver stiffness measurements through transient elastography alongside reported cannabis use. Results indicated that cannabis use overall was not associated with liver stiffness in patients with MASLD. However, among females, cannabis use was associated with MASLD accompanied by CSF, with an adjusted odds ratio (OR) of 0.47 (95% confidence interval [CI]: 0.24-0.91). Heavy cannabis use (9 to 30 times per month) was associated with MASLD accompanied by CSF among female participants, with an adjusted OR of 0.12 (95% CI: 0.02-0.88). Conclusion: In our study, cannabis use did not show a significant association with liver stiffness in patients diagnosed with MASLD. However, heavy cannabis consumption in women was associated with MASLD accompanied by CSF. These findings suggest that the effects of cannabis on liver health may differ based on gender and frequency of cannabis use, emphasizing the need for further research in this area.

Microglial morphological/inflammatory phenotypes and endocannabinoid signaling in a preclinical model of periodontitis and depression

BACKGROUND

Depression is a chronic psychiatric disease of multifactorial etiology, and its pathophysiology is not fully understood. Stress and other chronic inflammatory pathologies are shared risk factors for psychiatric diseases, and comorbidities are features of major depression. Epidemiological evidence suggests that periodontitis, as a source of low-grade chronic systemic inflammation, may be associated with depression, but the underlying mechanisms are not well understood.

METHODS

Periodontitis (P) was induced in Wistar: Han rats through oral gavage with the pathogenic bacteria Porphyromonas gingivalis and Fusobacterium nucleatum for 12 weeks, followed by 3 weeks of chronic mild stress (CMS) to induce depressive-like behavior. The following four groups were established (n = 12 rats/group): periodontitis and CMS (P + CMS+), periodontitis without CMS, CMS without periodontitis, and control. The morphology and inflammatory phenotype of microglia in the frontal cortex (FC) were studied using immunofluorescence and bioinformatics tools. The endocannabinoid (EC) signaling and proteins related to synaptic plasticity were analyzed in FC samples using biochemical and immunohistochemical techniques.

RESULTS

Ultrastructural and fractal analyses of FC revealed a significant increase in the complexity and heterogeneity of Iba1 + parenchymal microglia in the combined experimental model (P + CMS+) and increased expression of the proinflammatory marker inducible nitric oxide synthase (iNOS), while there were no changes in the expression of cannabinoid receptor 2 (CB2). In the FC protein extracts of the P + CMS + animals, there was a decrease in the levels of the EC metabolic enzymes N-acyl phosphatidylethanolamine-specific phospholipase D (NAPE-PLD), diacylglycerol lipase (DAGL), and monoacylglycerol lipase (MAGL) compared to those in the controls, which extended to protein expression in neurons and in FC extracts of cannabinoid receptor 1 (CB1) and to the intracellular signaling molecules phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt) and extracellular signal-regulated kinase 1/2 (ERK1/2). The protein levels of brain-derived neurotrophic factor (BDNF) and synaptophysin were also lower in P + CMS + animals than in controls.

CONCLUSIONS

The combined effects on microglial morphology and inflammatory phenotype, the EC signaling, and proteins related to synaptic plasticity in P + CMS + animals may represent relevant mechanisms explaining the association between periodontitis and depression. These findings highlight potential therapeutic targets that warrant further investigation.

Endocannabinoids and related lipids linked to social exclusion in individuals with chronic non-medical prescription opioid use

Opioid-related overdose deaths are still on the rise in North America, emphasizing the need to better understand the underlying neurobiological mechanisms regarding the development of opioid use disorder (OUD). Recent evidence from preclinical and clinical studies indicate that the endocannabinoid system (ECS) may play a crucial role in stress and reward, both involved in the development and maintenance of substance use disorders. Animal models demonstrate a specific crosstalk between the ECS and the endogenous opioid system. However, translational studies in humans are scarce. Here, we investigated basal plasma levels of the endocannabinoids anandamide (AEA) and 2-arachidonoyglycerol (2-AG), and eight endocannabinoid-related lipids, including oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), as well as whole blood fatty acid amide hydrolase (FAAH) activity in chronic non-medical prescription opioid users (NMPOU; n = 21) compared to opioid-naïve healthy controls (n = 29) considering age, sex, and cannabis use as potential confounders. Additionally, the association of endocannabinoids and related lipids with the participants' response to experimentally induced social exclusion was examined. We found significantly elevated basal AEA, OEA, and PEA levels in NMPOU compared to controls, but no differences in FAAH activity, 2-AG, or other endocannabinoid-related lipids. Within NMPOU, higher AEA levels were associated with lower perception of social exclusion. Robust positive correlations within N-acylethanolamines (i.e., AEA, OEA, and PEA) indicate strong metabolic associations. Together with our recent findings of elevated basal 2-AG levels in dependent cocaine users, present results indicate substance-specific alterations of the ECS that may have implications in the search for novel therapeutic interventions for these populations.

Cannabinoids as a Natural Alternative for the Management of Neuropathic Pain: A Systematic Review of Randomized Placebo-Controlled Trials

Dysfunction or damage to the nervous system may develop into and result in a chronic pain condition known as neuropathic pain. Neuropathic pain is defined as the structural and functional alteration of the somatosensory component of the nervous system. The treatment of neuropathic pain is a complex endeavor, which often requires specialist care and intensive drug therapy. Recently, cannabinoids have emerged as an alternative and natural option for the treatment of chronic pain, with tetrahydrocannabinol (THC) and cannabidiol (CBD) being the most extensively studied neuroactive components. The therapeutic potential of cannabis remains largely underexplored, primarily due to its social stigma and the restrictions that are in place on its cultivation. The primary aim of this systematic review was to explore the therapeutic value of cannabinoids in the management of chronic pain and thus achieve an improved quality of life for those patients. A systematic review of the literature published over the last two decades was performed using the following databases: PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Turning research into practice (Trip), and Google Scholar. Studies that were completed and published between January 01, 2000 and August 31, 2024, in English language, were extracted and appraised. A combination of keywords and Boolean operators Cannabis OR Chronic Pain OR End of life OR Pain Management AND Drug therapy was employed for data extraction. The Cochrane risk-of-bias tool for randomized trials (RoB 2) was used for risk-of-bias assessment. The initial search resulted in 125282 articles; 86,781 of the articles were identified as duplicates and were removed from the primary analysis, and 38,501 abstracts were thus screened. Abstracts, case studies, reports, editorials, viewpoints, cross-sectional studies, cohort studies, case-control studies, case series, and letters to the editor/correspondence manuscripts (n =38,492) were furthermore excluded. Nine full-text articles were critically assessed and tested against the inclusion and exclusion criteria, and a further four articles were excluded with a total of five placebo-controlled randomized control studies being ultimately included in the final systematic review. Compared to placebo, cannabinoids provided significant relief from chronic pain (33% vs 15%) as measured by the visual analog scale. The transdermal application of CBD led to a more pronounced reduction in sharp pain, according to the neuropathic pain scale. Minimal to no side effects were recorded, further highlighting the potential benefits of cannabinoids.

A Highly Potent, Orally Bioavailable Pyrazole-Derived Cannabinoid CB2 Receptor- Selective Full Agonist for In Vivo Studies

The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role of CB2R in pathophysiological conditions and for target validation in vivo, optimal pharmacological tool compounds are essential. Despite the sizable progress in the generation of potent and selective CB2R ligands, pharmacokinetic parameters are often neglected for in vivo studies. Here, we report the generation and characterization of a tetra-substituted pyrazole CB2R full agonist named RNB-61 with high potency (K i 0.13-1.81 nM, depending on species) and a peripherally restricted action due to P-glycoprotein-mediated efflux from the brain. 3H and 14C labeled RNB-61 showed apparent K d values of <4 nM toward human CB2R in both cell and tissue experiments. The 6,800-fold selectivity over CB1 receptors and negligible off-targets in vitro, combined with high oral bioavailability and suitable systemic pharmacokinetic (PK) properties, prompted the assessment of RNB-61 in a mouse ischemia-reperfusion model of acute kidney injury (AKI) and in a rat model of chronic kidney injury/inflammation and fibrosis (CKI) induced by unilateral ureteral obstruction. RNB-61 exerted dose-dependent nephroprotective and/or antifibrotic effects in the AKI/CKI models. Thus, RNB-61 is an optimal CB2R tool compound for preclinical in vivo studies with superior biophysical and PK properties over generally used CB2R ligands.